A glossary of tidal terms drawn from traditional, local, historical, topographical, literary, scientific and vernacular sources.
By Owain Jones & Heather Green
Contents of this page
A Note About the Glossary
Acknowledgements
Introduction
Breathings of the Moon Glossary
Select Bibliography
A Note about the Glossary
The majority of these terms were researched and written by Owain, others by Heather, and a handful of terms have been newly coined for things that we could not find words for when exploring the Severn Estuary together. These are indicated by HG & OJ. The terms eagre, gout and pîl were suggested by Owain’s brother, Rhyddian Jones.
Acknowledgements
Owain Jones
I am extremely grateful to Heather Green for her support, care, friendship and input into the glossary, especially this printed version. It is now part of a wider collection of collaborative work we are doing which, together, provides a process of conjoined Deep Mapping of the Severn Estuary and Bahía Adair in Mexico, an amazing tidal place known to Heather since early childhood. Together, Heather and I stress that this is more an artistic than scientific endeavour. Some factual errors might occur on occasions.
Heather Green
I am indebted to the Tides Institute for my summer residency with such an inspiring place to work on the design of the book, and also for the use of their library and permission to use some of their historic photographs for the illustrations. And of course, I’m grateful to my family, my dear friend and muse Katherine Larson, and to my incredible friendship and continued collaboration with Owain Jones. The tidal glossary is his original creation and continues to be an ongoing part of his Tidal Cultures website. I thought it might be amazing to realize it as a letterpress-printed artist book, which he graciously agreed to do. It’s been lovely to participate in shaping the text and to be able to add some ancillary words, especially ones that have more connection to my side of the pond!
Introduction
This Tidal Glossary began life on January 23rd 2015 as part of my Tidal Cultures blog. That blog emerged from a creative research exchange project I ran between 2012 and 2014, which curated a series of exchange visits between UK based artists and scholars with interests in the Severn Estuary, and northern Netherlands based artists and scholars with interests in the Dutch Wadden Sea. My co-applicant and co-leader on the project was professor Bettina van Hoven of Groningen University. The project was funded by The Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NL) and The Arts and Humanities Research Council (UK). Thanks to them, Bettina, and all who took part.
The Severn Estuary and Wadden Sea, although markedly different landscapes in many ways, are united by sharing extreme tidal ranges. The Severn Estuary has a huge tidal rise and fall and resulting areas of intertidal land. Whilst the tidal range in the Wadden Sea is not so extreme, it has even larger areas of intertidal space due to the local topography. Both places share sea walls, saltmarsh margins, mud and sand flats, winding channels, and all the entangled local ecology and ecology that is shaped by the tides, into what I have termed rhythm-patterns, as tides are, at once, temporal and spatial.
I have been fascinated by tides, and particularly the huge tides of the Severn Estuary and Bristol Channel, since I was a child, as I grew on a farm which bordered the estuary in one very striking place, The Lamby, east Cardiff, and also which worked fields on the Wentlooge Levels; ‘the moors’, as we called them, between Cardiff and Newport. I subsequently lived in other places on or near the estuary shore, always watching, or sensing, the tides which relentlessly rose and fell each day and night in their enthralling, changing, monthly and seasonal rhythms.
Counterposing this fascination with, and love of tidal places was a growing awareness of the impacts of modern society on nature in general and estuary landscapes in particular. The Severn Estuary has long been under threat from all manner of existing pressures and proposed developments, including vast barrage and tidal lagoon schemes. Many other UK estuaries have also been degraded by various pressures and face uncertain futures. A few have been entirely erased, such as the Taff/Ely estuary, west Cardiff. There, the daily tidal flow, and all the inter-tidal land and its rich ecology and culture was ended by the building of a barrage to create what is now the high-water only Cardiff Bay. The Tidal Cultures blog, and my other tide/estuary focused writings and ventures, were, in part, to raise awareness of these amazing and important landscapes and to express my care, love of and concern for them.
As I photographed and wrote about tides, estuaries, and the Severn Estuary in particular, first for an arts degree in Bristol (a famous tidal city), and then in my meandering ‘career’ as a cultural geographer, with interests in nature, tides, trees, the environmental crisis, place and memory, I have collected many books and other references. These are books about the Severn Estuary or parts thereof, other estuaries, and about tides more widely. It became clear to me that tides have, perhaps unsurprisingly, a very rich cultural heritage of local practices and technologies and words and phrases used to describe aspects of local tidal cultures. And it seemed like a collection of such words and phrases would be of interest, so the Tidal Glossary began. Also I was conscious, particularly in relation to the Severn Estuary, that much traditional, local, vernacular culture relating to tides was slowly fading out of use and out of collective memory, and thus the words also. So this endeavour sits alongside other efforts to collect, share and revive words for nature such as The Lost Words project by Robert Macfarlane and Jackie Morris. The Glossary can also be seen as a celebration of ‘place’ and ‘local distinctiveness’ as pioneered by the brilliant arts and environment group Common Ground.
In the Glossary I have focused on more ‘poetic’ rather than ‘technical’ terms, but there is some blurring across that boundary. Particularly there is a focus on local, vernacular, obscure and/or historic terms. In regards to the latter, tides were, of course, something of a mystery until the secrets of gravity and planetary motion were revealed by Sir Issac Newton. It is from that era that the title The Breathings of the Moon comes.
The words and terms range from many words about the differing states and stages of the tides; to terms linked to time and the Moon; to local names for tidal currents, sailing, fishing and coastal practices and technologies. Scientific books on tides, of which there are many, are replete with technical terms, but these are mostly not included. A few plants and animals are included, but this is generally not a tidal ecology Glossary, as such would be extremely long and complex. Some terms in the Glossary occur only once or twice in searchable texts. These include terms from a few novels and memoirs which might be personal to the writers alone.
The geographic epicentre of this collection is, inevitably, centered on the Severn Estuary and the UK beyond that. But other terms from more distant tidal places and from other languages are included as I have come across them in books (and websites) I have collected.
Owain Jones. Priston; Bath (UK); July 2026.
There are around 280 terms in the Glossary
Heather is working to produce a letterpress printed, illustrated, version of this text.
Last update 24 08 2026.
Breathings of the Moon Glossary
Word Cloud
Aestus. “The term estuary is derived from the Latin word aestus meaning tide, and refers to “a tongue of the sea reaching inland”. This is the opening line from the book, Estuaries: Monitoring and Modelling the Physical System by Jack Hardisty.
Age of the Moon. This is simply where the Moon is in its monthly cycle from new to full. Derek Howse; Some Early Tidal Diagrams. This is obviously critical to the state of the tides and closely tied to the next term.
Age of the Tide. First, this term refers to the stage of the tides within their monthly cycle. However, ‘Age of the Tide’ is also an old term for the lag between a new or full moon (syzygy) and the time of maximum spring tidal range. This was adapted from the glossary in Changing Sea Levels: Effects of Tides, Weather and Climate by David Pugh. The concept is well explained in Jonathan White’s Tides: The Science and Spirit of the Ocean, where he describes how the term relates to the lag between a new or full moon and the high tide it triggers a day or so later. This lag varies by location due to local coastal and oceanic circumstances that slow down or enhance the rise of the tide.
Amphidromic Points. Also called tidal nodes, amphidromic points are geographical locations where there is little or no difference in sea height between high tide and low tide. As such, the concept of amphidromic points is crucial to understanding tidal behaviour. The term derives from the Greek words amphi (around) and dromos (running), referring to the rotary tides which circulate around amphidromic points. It was first discovered by William Whewell, who extrapolated the cotidal lines from the coast of the North Sea and found that the lines must meet at some point.
Anchialine Pools. These are land-locked, mostly small bodies of water of varying salinity that are adjacent to the ocean. These pools have indirect, underground connections to the sea and thus show tidal fluctuations in their water level. They only occur in very specific coastal locations where underground channels to the sea run through rock strata such as lava formations or young limestone. They often have very unique biotic communities as with the many endemic (and endangered) species found in anchialine pools of Hawaii.
Apflod. Anglo-Saxon word for low tide. Hugh Aldersey-Williams; Tide: The Science and Law of the Greatest Force on Earth.
Aphelion, Perihelion & Apsis. The Earth’s orbit around the sun is slightly elliptical rather than perfectly circular. The aphelion is when the earth is farthest from the Sun in its orbit. This is one of the many varying factors which affect cyclical variations in tide height and range between different months and seasons. The aphelion is opposite to the perihelion, which is the Earth’s closest distance to the Sun in its orbit. This also affects the tides. Together the aphelion and perihelion are called the apsis.
Apogean Tides. Tides change monthly with the phases of the Moon, but the Moon’s orbit of the Earth—which is elliptical—also has effects on tidal range. The apogee is the orbital point when the Moon is farthest from the Earth. Apogean Tides become lesser as the Moon nears apogee, and increase again after the apogee is passed. As opposed to the perigee, and perigean tides.
Apsis. See Aphelion.
Armoured Mud Balls. Sedimentary structures known as armoured mud balls are created by tidal action that shapes mud into rounded egg-shaped ellipsoids by a back-and-forth rolling motion on an inclined platform, becoming fairly uniform in size. Sometimes particles such as sand, pebbles, or shells form an ‘armour’ that allows the mud ball to retain its shape during transport. These structures are occasionally preserved in ancient intertidal deposits, and the evaluation of their size, shape, armour composition, and orientation in relation to shorelines can be a useful paleogeologic tool. Mud balls (armoured and unarmoured) often form along the Severn Estuary and can be found on the beach during spring tides and storm surges. See Mud Balls.
Astronomical Tides; Lowest & Highest. Astronomical tides are those which are predicted in given places, taking into account only the major forces of the Moon, Sun and Earth’s movement. The heights and times of these are often changed by local circumstances, particularly atmospheric pressure and wind direction. Lowest astronomical tide (LAT) and highest astronomical tide (HAT) are as their names suggest.
Back & Fill. A sailing term; “To use the advantage of the tide being with you when the wind is not.”
Basket-Weir. A generic name for a tidal fish trip that, like other kinds, could be set and cleared at low tide. They were structures of posts and rails set seasonally (or longer) in an accessible intertidal area to which fish traps, baskets and nets of different kinds were attached in ranks. Fish were caught as they swam through when the weir was submerged. In the Severn Estuary, and similar places, there was very little visibility in the silty water, so the fish could not see the traps until too late. See Fish Traps; Fryke Net; Hedge Wier; Kype; Putcher; Putcheon; Putt; Stilbaai Tidal Fish Trap.
Bawley. Mostly associated with the Thames estuary and other southeastern tidal waterways of England, “these were sailing vessels typified by a boomless cutter rig and probably named for having a boiler for cooking shrimp in amidships”. The majority were built by Aldous of Brightlingsea, but they were also built in Harwich, Erith, Southend, Leigh, and on the Medway. Estuary, Rachel Lichtenstein.
Besid-Neap. An old dialect term for low tide. Nathaniel Bailey; English Dialect Words of the Eighteenth Century.
Big Run-Out. A term for a very low tide. I first came across it in the famous novelist, Jack London’s book,Tales of the Fish Patrol. As in; “to my surprise, I found barely a foot of water where we had dropped anchor in ten feet. It was the big June run-out of the full moon, and as the ebb had yet an hour and a half to run, I knew that our anchorage would be dry ground before slack water.” He also uses this phrase in the essay, Small Boat Sailing.
Black Mud. Heather Angel, Life in Our Estuaries, explains that if your footprints in estuary mud (generally grey) reveal a layer of black mud just below the surface, this is ‘ferric sulphide’ and an indication of anaerobic conditions.
Black Tide. This term is used in quotation marks in, C. M MacInnes and W. F. Whittard (eds.); Bristol and Its Adjoining Counties. They say it referred to ‘dead calm water’ at low tide when folk were fishing for salmon in the pools of the Severn Estuary. Presumably, the turbid water, with no waves or ripples on the surface, took on a mirror-like quality which shone black.
Blood Moon. On rare occasions the Moon appears as large and red—caused by the Moon being softly illuminated in a total lunar eclipse by sunlight that has bent around the Earth and thus through the earth’s atmosphere. (The same reason that sunsets are red). As this occurs at a moment of syzygy—when the Sun, Earth and Moon are inline—it coincides with spring tides. This magnifies the degree of ‘cosmic drama’ on show—high tides, red Moon—and there are many spiritual associations with blood Moons.
Brackish. A generic name for water found in estuaries and other tidal/coastal places which is a mix of saltwater and freshwater. The movements of the tides are critical in the creation of brackish water and the degree of its salinity. This, in turn, affects the biodiversity of brackish areas. Waters of differing salinity have differing scientific names. See Salinity.
Breathings of the Moon. This comes from a quote from the Venerable Bede (Saint Bede), one the great Anglo-Saxon scholars, when trying to describe and explain tides. Scholars of that era knew tides were linked to the Moon’s phases, but not knowing of gravity, cast around for other explanations. To quote Beade, “But the most admirable thing of all is the union of the ocean with the orbit of the Moon. At every rising and every setting of the Moon the sea violently covers the coast far and wide, sending forth its surge, which the Greeks call reuma; and once this same surge has been drawn back it lays the beaches bare, and simultaneously mixes the pure outpourings of the rivers with an abundance of brine, and swells them with its waves. As the Moon passes by without delay, the sea recedes and leaves the outpourings in their original state of purity and their original quantity. It is as though it is unwittingly drawn up by some breathings of the Moon, and then returns to its normal level when this same influence ceases.” The Venerable Bede; Opera de Temporibus, Section XXIX.
Brob. This is the name given to laurel branches which were cut and used as way-markers for safe walking on intertidal sands in Morecambe Bay (England). It is an old, and maybe local, custom and term. Seen in The Gathering Tide by Karen Loyd and also in an essay by her. In this she says, “the guides have used laurel branches for centuries for marking the safe crossing routes over the sands. Their thick leaves stay on the branches even when submerged daily by the tide”.
Cailleach. An ancient Celtic pre-Christian goddess/witch. She was associated with nature, winter, storms, and tides. One legend has her home at The Gulf of Corryvreckan (Coire Bhreacain—Brecan’s cauldron) in Scotland. This strait, situated between two islands, Scarba and Jura, is notorious for its extreme tidal flow and turbulence. Adam Nicholson; Life Between the Tides.
Cart Shanker (Shanker). Shankers were shrimp fishers on the Lancashire (UK) coast. This involved trawling for shrimp with a net drawn behind a horse and cart when the season, tide height (low tide) and conditions were suitable. This was a locally preferred method for catching brown shrimp as it was cheaper and easier than fishing with a boat. This fishing method features in the novel Seascraper, Benjamin Wood.
Change Moon. Another name for the new Moon. Howse; Some Early Tidal Diagrams
Coming Tide. Another way of saying flooding (rising) tide. (As opposed to Going Tide). Peter H. Spectre; A Mariner’s Miscellany.
Co-tidal Lines. Lines on tidal charts that pass through places which have the same range of tide, or places which have the same Lunitidal Interval.
Cribbing/Crib (also Cribb, Cribbe). This was a name for breakwaters built of wood, stone or other materials such as a sunken boat filled with stone, put in place to protect wharfs and land from erosion at high tide. It is a name reckoned to be unique to the Severn Estuary. The earliest forms of cribbing, sometimes also called faggoting, comprised horizontal layers of brushwood, probably originally placed in bundles, and held in place by vertical wooden stakes and horizontal wooden elements, these materials being derived from the coppicing of nearby woods.
Crom’ubhán (Crom’bhuán). An Irish word for a long stick with a hook on it used to lure the crabs out of their underwater rock holes at the very lowest tides. The stick had to be pulled very swiftly towards you. “It was possible to get the odd lobster this way too”. Manchán Magan; Sea Tamagotchi.
Cycle of Meton. Named after Meton of Athens who discovered a repeating nineteen year cycle, where the Moon phases happen again on the same days of the year in four hundred thirty-two BC. Nineteen years are equivalent (nearly) to two hundred thirty-five lunations. This period is called the ‘Cycle of Meton’, or ‘Metonic cycle’. Manual of Tidal Prediction.
Dark Moon. There are various versions of what a dark Moon is. It is often regarded as the same as a new Moon when considering tides. But there is a brief period in the Moon’s cycle when it is not illuminated by the Sun at all, and is thus invisible in the night sky. This is just before the new Moon appears as the slenderest crescent. A dark Moon is associated with spring tides as it is when the Sun, Earth and Moon stand in a straight line, and their tidal pull combines to full effect on the oceans.
Dead Waters. As opposed to lively waters. Aldersey-Williams says that Bede discussed the sea in these terms (in medieval Latin), with lively waters being high/spring tides and dead waters the reverse.
Dead-Low Water. Denotes the very lowest point of an ebb tide. This was seen in Joan Tucker; Ferries Of Gloucestershire.
Double Low Water/Double High Water. In certain locations, because of local coastal topography, periods of low and high water have an extra mini rise and fall e.g., Hoek Van Holland (double low) and Southampton, England (double high).
Dead with the Tide. This phrase occurred in a BBC Radio adaptation of the famous adventure story, Treasure Island by Robert Louis Stevenson. As in, when the ship central to the adventure first sets sail from Bristol Docks, they do so ‘dead with the tide’. This would be at the high point of the tide, when the water level would be high along the length of the River Avon and the beginning ebb help the ship—The Hispaniola—on her journey downstream to the Bristol Channel. We can’t find many other uses of this phrase.
Dip. This is a term relating to sea mines deployed during war time and the effect tides can have on them. Some mines were tethered by weight to the sea floor so they were not visible at the surface. Dip is when a strong ebb current pushes mines lower in the water than they were intended to be, and thus below the depth of ship hulls they were targeting. Mines were deployed in the Irish Sea and Bristol Channel by both British and opposing German forces. Commercial shipping had to risk the mines if they were to keep trading. It became known that passage at times when the strong tides were causing dip in the mine fields was safer.
Drying Mooring/Drying Harbour. A mooring where a vessel is left on sand or soft mud at low tide instead of staying afloat in deep water. Drying harbour—where an entire harbour is clear of water at low tide. Tenby in Pembrokeshire, South Wales, is one of many examples around the British coast.
Drudging. This is a means of controlling the direction of a sailing boat when sailing in a tidal current when there is little or no wind. An anchor is dropped from the stern and dragged along the seabed to try to ensure the craft maintains the desired course. This seems particularly associated with the Thames barges which worked up and down that great estuary. Maurice Griffiths; The First of the Tide.
Dulse. Dulse harvesters in the Bay of Fundy wait for a special combination of warm weather and extra low tides, then head out to the dulsing grounds—the rocky intertidal flats where the edible red seaweed grows. Picked and sun-dried, dulse is a nutritious regional specialty, either sold to food companies or kept for personal use.
Dutch Fair. A fair, or market, on Great Yarmouth beach (England), but I think other places too, when Dutch barges would beach at high tide, sell goods to local shoppers, then set sail again at the next high tide. There is quite a famous painting by George Vincent of a Dutch Fair. Aldersey-Williams quotes a source; “The “Dutch Fair”, as it is denominated, is held on the beach, and presents an interesting appearance. From twenty to thirty of their flat-bottomed boats are run on the shore at high water, and as the tide recedes, are left high and dry. Dutch pipes, dried flounders, wooden shoes, apples, and gingerbread are then offered for sale, and if the weather be fine, the beach is thronged with company, many of whom come from a great distance.”
Éadálacha. An Irish word for wood or oil barrels that come in on the tide. Spoil, salvage, finds, or rafta—a big collection of sea plunder gathered together. Magan; Sea Tamagotchi.
Eagre. A dialect word for a tidal bore/wave. This appears in George Elliot’s novel The Mill on the Floss.
Ebb. Tide falling to low tide. As opposed to Flood.
Ebb Current. Currents in the sea generated by the falling tide. Ebb currents generally set seaward, i.e., away from the shore. Also called an outgoing stream.
Elver Tide. From Brian Waters’ book, Severn Tide. There are lengthy descriptions of elver fishing on the Severn in this book. He talks of how ‘Elvers are fished for the length of Severn tide, from Lydney to Tewksbury’, he describes how, where and when to fish was in part determined by the state of the tide (and the season). He says that some ‘elver tides’ were more productive than others.
Emersion. “The process of emerging from water after being submerged”. This term can also apply to celestial emergence after an eclipse, or emergence into view more generally. This obviously applies to things emerging out of the sea as the tide falls. The Encyclopedia of Tidepools and Rocky Shores edited by Mark W. Denny, Steven Dean Gaines uses this term in relation to tidal rise and fall.
Epact. The difference in days and fractions of a day between twelve lunations and the civil year. The average amount is about ten days fifteen hours (eleven days fifteen hours in leap years), and there will thus be this difference in the Moon’s age at zero hours on January 1st in successive years. The epact of the year is the Moon’s age at zero hours on January 1st. Manual of Tidal Prediction.
Equinoctial Spring Tide. When the Moon and Sun are in conjunction on the equator, this tends to bring larger than usual spring tides. Philip L. Woodworth; Tidal Science Before and After Newton.
Establishment of the Port. A phrase meaning the coming of the high tide to a port which made it navigable. This is discussed in Howse who also reports that one Admiral W. H. Smyth, in The Sailors’ Word Book, criticised it as “an awkward phrase to denote the tide-hour of the port”.
Estero. The Spanish word for ‘estuary’ or ‘inlet’. This term is derived from the Latin word aestuarium, referring to a body of water where a river meets the sea, often characterized by brackish water and tidal influence. The word is also used
specifically to describe a negative estuary, one fed from tidal inflow of seawater, where there is no freshwater inflow as from rivers, only occasional ephemeral streams. Esteros are hypersaline, with the salinity higher at the back of the marsh, rather than the other way around as in classic river-fed estuaries.
Estuary English. This has a modern meaning, but John R. Stilgoe talks of an older form of language – ”the marshland vocabulary, which local people living in marshy coastal needed and perpetuated as the negotiated daily life in these very distinctive, shifting and in some ways dangerous environments”. Shallow Water Dictionary. A Grounding in Estuary English John R. Stilgoe. See Tidal French.
Euryhaline. A term for organisms that can adapt to a wide range of salinities (fresh, brackish, or salt water), so ones that are adapted to tidal places like estuaries and tide pools.
Fall, Tidal. Often, when the tidal range in a place is given, it is done so by height of tidal rise. But sometimes the reverse is used, Smith and Ralph say, in their History of Bristol and Gloucestershire, “the broad [Severn] estuary has one of the largest [tidal] falls in the world”. Thus, the fall equates to the ebb.
Falling Tide. An ebbing tide.
Fill of the Tide. A term for the rise of a tide. From Karen Lloyd’s book, The Gathering Tide: A Journey Around the Edgelands of Morecambe Bay: “Sailing ships had waited at anchor for the fill of the tide”.
First of The Tide. An expression sometimes used to denote the beginning of a flooding tide. For example, the memoir of sailing in the tidal waters of the mouth of the Thames Estuary by Maurice Griffiths, is entitled The First of The Tide. There is also a song of the same name by Erland Cooper.
Fish Trap/Weir. Various forms of fish traps and weirs, which rely on tidal rise and fall, have been used for catching fish throughout history in tidal locations. They are structures such as stone enclosures, or wooden frames holding nets or baskets, which were built in accessible intertidal areas, and which catch fish when the traps were submerged. Differing traps were set to catch fish on both the flood and ebb tide. Some weirs were simply pools made by piling up low stone walls in which fish became trapped on the ebb, and then easy to catch with nets. The Severn Estuary had many fish weirs and traps along its shores for centuries. Early traps were stone weirs; later ones became highly refined weirs of different kinds of baskets for differing kings of catch. See also Basket Wier; Fryke Nets; Hedge Wier; Kype; Putcher; Putcheon; Putt; Stilbaai Tidal Fish Traps.
Flash-Lock. Flash-locks were constructed on rivers to create high water for mills and also to aid the movement of boats when water levels were low. They are not especially linked to tidal rivers, but there were a number on the tidal Thames according to Alwyne Wheeler, The Tidal Thames. They aided navigation when the river level was low due to the tide. Boats would wait in the lock and then be hastened downstream on a rush of water as the lock gate was opened. These very simple locks are said to date back to Roman times. There are discussions about there being conflict between millers, who wanted high water in the lock to drive their mill wheels, and those wanting to open the lock for navigation, thus releasing the water to rush downstream.
Flo & Esbe. Rising tide and falling tide from The Hague Atlas of 1541-7: quoted in Howse Some Early Tidal Diagrams.
Flo (2). Relating to the above; on some older maps, river mouths and estuaries were marked as ‘Flo’. For example, on a map of 1611, showing the ancient county of Cheshire, created by John Speed and engraved by Jodocus Hondius, the Dee and Mersey Estuaries are marked as the Dee and Mersey Flos.
Floating Harbour. A harbour or port with permanent high water, as opposed to water that rises and falls with the tide. Most ancient and mediaeval posts in tidal locations would have been tidal harbours. Boats would have to settle on intertidal at low tide, and float again at the next high tide. Large ports such as Bristol (UK) were tidal ports until large engineering efforts created permanent high water using locks in the nineteenth century. See Drying Harbours.
Flood. The flood is the tide rising to high tide. This is opposed to the ebb—tide falling.
Flood Current. “The horizontal movement of water associated with a rising tide. Flood streams generally set toward the shore, or in the direction of the tide progression. Also called flood, flood current or in going stream.”
Flood Gulls. A term from the great Rachel Carson’s book Under the Sea-Wind referring to Black Skimmers, ‘Because they fed on the rising tide, the skimmers were called flood gulls… “The flood gulls circled the island and crossed and recrossed”.
Flood Water. The water of a coming high tide. Also, Tide Water.
Flow of the Moon. An expression concerning the direction of movement of the Moon in the sky. One of the indicators mariners used to try to predict tide times and currents. Howse, Some Early Tidal Diagrams.
Flux of the Tide. An old term for the flood tide. This appears in Daniel Defoe’s book, The Storm. The opposite term is Reflux of the Tide—the ebb.
Foam Line. A foam line can sometimes form and run up the middle of an estuary on an incoming tide. This is caused by the complex interactions between various forces in the estuary, including the friction created by the banks, and the mixing of water of differing salinity. Tides a Very Short Introduction; Bowers and Roberts.
Foul Tide. A tide which is hindering sailing progress by flowing against the desired direction of travel. This phrase appears a few times in Francis B. Cooke; In Tidal Waters.
Fresh (The). An old term simply for fresh water as opposed to salt/sea water. This is from Daniel Defoe’s book 1703, Storm, which describes the great storm of that year, using eyewitness testimony. “But the Wind throwing the Tide very strongly into the Severn, and so into the Wye, on which Chepstow is situated. And the Fresh in the Wye, meeting with a Rampant Tide, overflowed the lower part of our Town”.
Freshes. Found this in Henry Irving’s book; The Tidal Havens of the Wash and Humber. There are areas of estuaries and coastal marshland called freshes. For example, Stiffkey and Blakeney Freshes, in Norfolk (UK). These seem to be fresh water marshes, which are part of a coastal/estuarine landscape, but where tidal ingress has been excluded by sea defences. They are often of great wildlife value for both flora and fauna.
Full Sea. A term for high tide/high water. Howse, Some Early Tidal Diagrams.
Full Tide. Very similar to the above. Meaning when the tide is at its highest in any given cycle. Often used in conjunction with ports and ships embarking. I heard this in a BBC Radio adaptation of Robinson Crusoe by Daniel Defoe. The term also appears in the famous poem Dover Beach by Matthew Arnold.
The tide is full, the moon lies fair
Upon the straits; on the French coast, the light
Gleams and is gone; the cliffs of England stand,
Glimmering and vast, out in the tranquil bay.
Fyke Net. (Fyke Netting). Fyke nets are a kind of fish trap. They consist of long tunnel nets tapering to a point, held open at the mouth and side nets to guide prey to the opening. They were staked out in shallow water areas. See Fish Traps; Hedge Wier; Kype; Putcher; Putcheon; Putt; Stilbaai Tidal Fish Traps.
Fylleflod. Anglo-Saxon word for spring tide. Aldersey-Williams, Tide: The Science and Law of the Greatest Force on Earth.
Gaothannaí (Gúthannaí). An Irish word for the streams or channels of water on the strand when the tide is out and the rest of the beach has dried. They can be deep enough that you need to take your shoes and socks off to wade through. It can also mean gaineamh beo, sinking sand; places where large rivers are feeding into the sea when the tide is going out. They can be dangerous: you sink to your knees and aren’t able to get out. Magan; Sea Tamagotchi.
Going Tide. Another way of saying ebbing (falling) tide. As opposed to the coming tide. Spectre, Mariner’s Miscellany.
Golden Number of the Year. Howse explains that in the Brouscon Almanac,1546, there was a means of telling the age of the Moon from the calendar of Christian feast days—some which are moveable in relation to the Moon (like Easter)—and others immovable with a fixed date. These in turn were linked to the Golden Number of the Year, which tracks the nineteen-year lunar cycle where Moon phases fall on the same calendar days. Together these date cycles were used in calendars (computus) to predict new Moons and full Moons and the spring tides that came with them.
Gout. A name for tidal outfall flaps or older discharge infrastructures, certainly used in South Wales, and particularly the Gwent and Wentlooge Levels. These allow reens (rhines) to drain seaward at low tide, but closed to prevent inland flow at high tide. There are accounts of the Old Stone Gout at Peterstone, Wentlooge Levels, South Wales.
Gridiron. A large grid-like platform of iron, or large wooden beams, set at a height between high and low water, on which vessels could be rested to be worked upon externally at low tide. Many harbours and ports have these near their entrances. The one that stands just out from the locks that make the floating harbour in Bristol (England) is now disused and hidden under banks of silt and mud deposited by the tides.
Grunion. A fish similar to sardines known for their unusual mating ritual carefully timed with the tides. Their large, fast-moving mating populations create quite the spectacle, and an easy feast for birds! As such, the process needs to be quick as lightning so they can return safely to sea. University of Arizona Ichthyologist Donald A. Thomson developed a formula to predict precisely when and where the Grunion would beach for spawning, occurring between one and six days after each full or new Moon. The eggs remain buried in the sand for about two weeks, and then hatch and return to the sea helped by the tide.
Gut. A gut is a narrow channel, either natural or engineered, through which water flows at pace, especially as tides rise and fall. Guts in some harbours would block up with silt, or even shingle, deposited by a flowing tide. A gut in Porlock harbour (Somerset, England) used to be cleared regularly by holding water back at high tide with a sluice and then releasing it in a rush to flush shingle away.
Half Tide. A term that means that a tide is half way between low water and high water, or vice versa. The state of the tide being, obviously, important to sailors and others concerned with the sea and its margins. The painter Edward Seago painted many tidal scenes, some of his works having ‘half tide’ in the title. Two examples are; Barges at Half Tide, Pin Mill, Suffolk; and Half Tide, Waxham.
Half Tide Cross. Possibly a marker which denotes half tide in a given location. There is such a cross on the Cornish coast at Bude (England). Certain tides are at half way when the water is level with the horizontal element of the cross. There are numerous photos of this cross online.
Half Tide Passage. I found this in Henry Irving’s book, The Tidal Havens of the Wash and Humber. The book is a ‘pilot’ which gives instructions and maps of how to safely sail into the small harbours and creeks of the area. A half tide passage means that the water in a channel is deep enough for the safe navigation of small craft for about half the time between high tide and low tide. Below half tide navigation becomes harder, depending on the size and draft of any given craft.
Half Tide Rocks. Rocks that are just visible at half tide in a given place. A natural alternative to the Half Tide Cross above. This phrase appears a number of times in Cooke; In Tidal Waters.
Head of the Tide. Tidehead. See Normal Tidal Limit.
Heahflod. Anglo-Saxon word for high tide. Aldersey-Williams.
Hedge-Wier. A kind of fish trap that could be built, and left in place, at low tide and checked at following low tides. A variation of the Basket Weir—these were ranks of traps set on stakes in the intertidal area. A funnel of fencing (thus hedge) opened away from the traps to guide fish towards them when the tide was flowing in. See Fish Trap; Fryke Net; Kype; Putcher; Putcheon; Putt; Stilbaai Tidal Fish Trap.
Horizontal Parallax. For tidal purposes, this is an angle at the centre of the Moon that is subtended by the Earth’s radius. It is therefore an indication of the Moon’s distance from the Earth, and consequently is connected with the Moon’s pull on the waters of the Earth. Manual of Tidal Prediction.
Hydrogeographer. One who studies and maps the physical aspects and processes of the seas and coasts. In Britain they became particularly important as they began to map the estuaries, showing in amazing detail the tidal sandbanks and channels of many of the estuaries which were important shipping routes. In around 1693, a map of the mouth of the River Dee, showing its tidal geography was drawn by the British coasting pilot Captain Greenville Collins.
Inning. This is a traditional method of reclaiming land in estuaries and other tidal areas. It involves constructing structures in an intertidal area that slow down tidal flow. As a result, more sediment is deposited at high tide, gradually raising the land level. After a certain period, the area can be enclosed and fully reclaimed. Since this is land built by sediment, it can become highly fertile for agriculture.
Insular Tide. Tides which can have unique patterns around coastal islands and tidal islands, caused by narrow straights, shallow sea beds, reefs and causeways.
‘Kopehe. A Passamaquoddy (First Nations people, Bay of Fundy) word describing the rising tide surrounding or cutting off access to a rock, island, etc.
Kypes. A complex woven fish trap. These were put out on basket weirs in long lines perhaps 3 ranks high. They consisted of three woven parts, the putt, butt and firwell, which wedged together to make a very large funnel. The smallest point of the funnel, the firwell, was very tightly woven into a mesh to catch shrimp. They were generally set pointing upstream to fish on the ebb tide. In some accounts on the Severn estuary these are called putts not kypes.
Lag trá, (lom trá). An Irish term describing when there’s a wide beach visible at low tide. Sometimes also known as scilteacha trá on Toraí. Magan; Sea Tamagotchi.
Lagging of the Tide. The periodic retardation in the time of occurrence of high and low water due to changes in the relative positions of the Moon and the Sun.
Last of the Tide. An expression sometimes used to denote the last hour of a flood tide, when setting sail is still just possible. In the memoir of sailing in the tidal waters of the mouth of the Thames Estuary by Maurice Griffiths called The First of the Tide, he writes of setting sail on ‘the last of the tide’, just in time to avoid being stuck on mud flats at low tide.
Lathe Net. A large hand-held net used for fishing in tidal waters by wading through the rising tidal margins. Mostly associated with fishing for salmon in the Severn Estuary.
Lee Tide (Leeward tide). A tide which is flowing in the same direction as the wind. Thus the height of tide might be amplified when wind is pushing water onto the coast, or into an inlet or river mouth; the time of high tide and turn of the tide might be slightly pushed forward.
Lift of the Tide. This is the difference in the height of tidal water between low and high tide and the height of water above low tide, at a given place and time. As in, “[B]y far the most important part of the river, in this point of view, is that below Sharpness Point, for there the whole trade to and from Gloucester has to pass. There, however, little improvement is necessary, for the great lift of tide ensures, at the proper times, ample depth of water.” William Parkes; On the Estuary of the River Severn.
Líonán. An Irish word for the rocky benthos in shallow waters that ships often hit. The líonán are only visible during a very low tide. Boilgeacha are similar, except they can be seen above the sea at times. Magan; Sea Tamagotchi.
Little Tide. This is a term for a neap tide which was local to Somerset, England. As opposed to Long Tide.
Lively Waters. Aldersey-Williams says that Bede discussed the sea in these terms (in medieval Latin), with lively waters being high/spring tides and dead waters the reverse. As opposed to Dead Waters.
Long Tide. This is a term for a spring tide which was local to Somerset, England. At spring tides, on some parts of the Somerset coast, the sea’s margin moves up to a mile in the space of six or so hours; perhaps this explains these twinned terms. As opposed to Little Tide.
Low Tide Day(s). At spring tides, when the low tides are at their lowest and the largest area of intertidal land is exposed, a few groups and bodies seek to encourage or organise Low Tide Days, where people can explore the intertidal zone and see the many wonders thereof. Common Ground, in their book England In Particular say, “we should celebrate Low Tide Days and enjoy archaeological as well as ecological explorations”. In 2004, the organisation CoastNET ran a funded project called ‘Celebrating Our Coastal Heritage with Low Tide Days”. See Low Tide Walks.
Low Tide Walks. All tides on beaches when the tide is receding, or fully out, can be considered to be Low Tide Walks. But there are also walks that can only be done at very lowest tides; so a few times a year only, or even less than that. For example, around a headland from cove to cove, or to a tidal island. There is a page dedicated to these on the Tidal Cultures website.
Low Water Channels. These are channels in places like estuaries and tidal river mouths, where water still flows at low tide, thus sometimes being used for navigation even at low tide. William Parkes, in Report on the Severn Estuary, describes the lower water channels in various stretches of the estuary.
Low Water Landing Stage. A landing stage for vessels to use when the tide is low/out. There is one in Tenby (Pembrokeshire, Wales, UK)—a long walkway on wheels that can be towed to the water’s edge by a tractor. These are important, in that and many other places, to ensure that tourist boat trips, including those to nearby Caldey Island, can take place throughout the day.
Lower Shore. A term for the lower areas of the overall intertidal zone. See Zonation.
Lunation. A word for the monthly cycle of the Moon.
Lunitidal Interval. This is the time lag between the transit of the Moon over a location and the next high tide. Knowing the lunitidal interval of a given location was an important way of predicting times of high and low water by observing the Moon. It is now not much used for navigation, being replaced by modern systems.
Make. The ‘tide makes’ was a way of saying the tide is rising. Example: “we proceeded by the Solway Frith, to Carlisle. You must know, that the Solway sands, upon which travellers pass at low water, are exceedingly dangerous, because, as the tide makes, they become quick in different places, and the flood rushes in so impetuously, that the passengers are often overtaken by the sea and perish.” Tobias Smollett; The Expedition of Humphry Clinker.
Maretazo. This is a name for periods of large destructive waves which impact the Pacific coast of Peru and Ecuador. These occur when certain weather conditions combine with spring tides. A news video of a Maretazo affecting Peru in 2024 can be seen online.
Mareograph. A tide gauge. Some mareographs are simple devices with a vertical measure fixed to a dock wall showing water level height. Other gauges are more substantial structures with recording devices that keep a record of the changing sea level. A notable example is the Cascais Tide Gauge in Lisbon, Portugal.
Marigram. “Any graphic representation of the rise and fall of the tide. Time is generally represented by the abscissa, and the height of the tide by ordinates.” The abscissa is the horizontal axis on a graph, the ordinate is the vertical axis.
Mascaret. This is the French word for a tidal bore. Interestingly—the River Seine, which famously flows through Paris, had a very powerful bore which attracted crowds of sightseers and was captured in old film and photographs. Today the Seine mascaret is much reduced in force and range by changes made to the river.
Mean (Lows; Highs, Springs). As the tides in differing places go through a complex set of cycles: daily, monthly, seasonally; mean (average) water levels are estimated for many locations such as ports and harbours. These means are listed as follows. For Low Water: Mean Low Water; Mean Low Water Springs; Mean Lowest Low Water; Mean Lower Low Water; Lowest Normal Low Water; Mean Sea Level (when all tide highest high and low are averaged out). For High Water:- Mean High Water; Mean High Water Springs; Mean Higher High Water. In some ways the highest tides are the most significant (e.g for flood risk), so special attention is paid to the Mean High Water Springs. “Monthly [high] tides are defined as ‘Springs’ or ‘Spring Tides’ when the tidal range is at its highest and ‘Neaps’ or ‘Neap Tides’ when the tidal range is at its lowest. The height of Mean High Water Springs (MHWS) is the average throughout the year of two successive high waters during a 24-hour period in each month when the range of the tide is at its greatest.
Merse (Merses). This is defined as “alluvial, often marshy land by the side of a river, estuary or sea.” Some areas along the shore of the Solway Firth are known as the merses. They get inundated by the higher tides, and form part of the Wildfowl and Wetlands Trust (WWT) reserve Caerlaverock Wetland Centre. The WWT posts bird sightings such as of peregrine falcon on the merses on their website.
Middle Shore. A term for the middle areas of the overall intertidal zone. See Zonation.
Mud Balls. Pieces of clay that are rolled into regular ovates (egg shapes) along the sea floor by the movement of rising and ebbing tides, which are then left exposed as the tide falls. The clay mud is sticky and firm enough to resist being dissolved by the sea water. When the weather allows, they dry into hardened forms and can be collected. See Armoured Mud Balls.
Mud-Gutting. This is a term for playing in small muddy creeks at low tide. It was likely made up by a family who lived on Canvey Island in the Thames Estuary. Kate Monson, in her PhD (Brighton University) about growing up on Canvey Island in the Thames Estuary, and in an article for the Slow Ways website recalls Mud-Gutting with her mother.
Mud Horse. A kind of sled for moving across mudflats that are too soft to walk upon. They are used for various forms of intertidal fishing and harvesting, especially in the Severn Estuary (UK). In order to use, one stands at the back of the sled, which takes most of your body weight as you lay forward on it, using your legs as propulsion.
Mud Patten. A traditional type of ‘shoe’ for walking on mud flats. These were used for wildfowling and accessing fish traps at low tide.There are films on how to make and use mud pattens online.
Mud Punt. Mud punts were large and shallow rectangular craft used to carry dredged mud away from the docks on the Clyde (Scotland). They were unpowered and had no sail, thus punts. They were often tied together to make large convoys for moving the mud, which was forever washing in on the tides and silting up the docks and navigation channels; The Clyde is a shallow river. The mud was loaded by dredgers and then moved to be shovelled off, either into deeper water, or in efforts to build up land on the nearby shore. The operation had to follow the rhythms of the tides. The wrecks of a large number of mud punts can still be seen in the Newshot Ship Graveyard. These are covered by each high tide and will gradually disappear into the mud they once moved. Mud punts may have been in use elsewhere, a record of a mud punt being built in Sheerness Dockyard in 1833 is recorded in the archives of The Historic Dockyard, Chatham.
Mudlark. (Mudlarker) “A person who scavenges for usable debris in the mud of a river or harbour”, almost inevitably at low tide. Mudlarking the act of doing so. Some mudlarkers in London have social media profiles with many followers. They report many interesting finds with historical interest. In some other cases mudlarks were not seeking finds at low tide, but moving mud around at low tide to clear slipways for safe boat access.
Neap Tide. When the tidal range in the monthly lunar cycle is at its minimum, the Sun and Moon pull the Earth’s waters at right angles. This causes low-variation neap tides (from nep meaning ‘scant or lacking’) at the time of the first and third quarters. In other words, the low tide is least low and the high tide is least high. Neap tides are the opposite to spring tides, and vice versa.
Negative (or Inverse) Estuary. In arid areas ‘negative estuaries’ may form. If evaporation exceeds freshwater input, the back of the estuary becomes a source of dense water saltier than seawater. Seawater enters at the surface and saltier water from the back of the estuary flows out below. During World War Two, German and Italian submarines used these submerged currents of salty water to sneak past the British naval base at the Strait of Gibraltar. The film Das Boot includes a scene depicting this, as the submarine cuts all power and silently drifts through the Strait, leaving the Mediterranean and heading out into the Atlantic. See Estero.
Nepflod (Niptid). Anglo-Saxon word for neap tide. Aldersey-Williams.
Nets. Many kinds of nets were used for intertidal fishing. In the Severn Estuary these included, Eel, Fryke, Long, Shrimp, Lathe, Stop and Swing. Some were fixed as fish traps, others, called Stop Nets, operated between two boats, and others called Long Nets operated from the shore or from wading out in shallow water.
New Cut. These were new channels dug out to make stretches of rivers navigable. They might have been dug to eliminate a meander in a river, but they were also used in tidal settings. When the tidal docks in Bristol (UK) were made into a floating harbour, with permanent high water contained by locks, a new cut was dug around the docks to allow the tidal river to continue west. A new cut was dug in the Dee Estuary (UK) to keep Chester as a port when the estuary had silted up to the point where navigation of larger ships was no longer possible. But this too soon fell out of navigable use due to silting.
Normal Tidal Limit. A term denoting the very upper limit of a tidal reach on a waterway. This is usually marked by a lock, weir, dam or sluice. In a few places the tide reaches a ‘natural’ limit. i.e. where the high tide can reach if unimpeded by anthropogenic interference. Also called head of the tide or tidehead. In the UK these often mark the boundary of the jurisdiction of The Marine Management Organisation (MMO).
Oaze. Old English for areas of ooze or tidal mud flat. There are a number of named Oazes shown on detailed maps of the Severn Estuary.
Oligohaline (Tidal) Marshes & Waters. These are brackish waters with lower levels of salinity, and salt marshes that relate to them. Oligohaline waters are 0.5–5.0 parts per thousand (PPT). This is the least saline of brackish water and is found in the upper reaches of estuaries where fresh water predominates. Salinity varies with the changing tides and with the amount of fresh water discharging from inland waterways.
Overfalls (Tidal Overfalls). Areas of rough sea, such as standing waves, caused by tidal flow, especially fast flow at times of ebb and flood, washing over areas of rough rocky seabed and sharp ridges in the seabed. I learned this via David Gange talking on the radio about his book The Frayed Atlantic Edge: A Historian’s Journey from Shetland to the Channel.
Overtides. These are variations in tidal heights and frequencies caused by local conditions, such as water body depth and coastal configuration. For example, Jonathan White says overtides occur off the coast of Argentina in the shallow waters of the Patagonian Shelf.
Palm Tide. A number of older regional studies of Gloucestershire say that the largest Severn Bores would occur in conjunction with the ‘Palm Tides’ of March. Presumably this is a religious reference to Palm Sunday.
Paqtlusg’teg. A Mi’gmaq word (First Nations people, Bay of Fundy) for an extremely low tide.
Peat Hag. I saw this term in Peter Finch’s book about the Severn Estuary, Edging the Estuary. A peat hag is a low mud cliff with an overhanging turf fringe. They occur in salt marshes where the flowing tide is eroding the edge of the marsh and also carving gullies into the marsh. The term is also commonly applied to freshwater bogs and marshes where mud cliffs and hillocks are exposed in some way. See Turves; Overhanging and Fallen.
Perigean Tides. Tides of increasing range, and currents of increasing speed, occurring monthly when the Moon is nearing perigee—when it comes closest to Earth in its elliptical orbit. As opposed to apogee and Apogean Tides.
Perihelion. See Aphelion.
Pîl (also Pill). This is a name, local to Southwest England and Wales, for small tidal creeks, and/or the tidal outlets of streams emptying into a sea or estuary. Some were used as small coastal trading harbours. Some are still used today. For example Oldbury Pill, in the Severn Estuary.
Pill Hobbler. Pill is a village on the tidal Avon near Bristol, UK. It is famous for being home to generations of Hobblers whose work was intimately linked to the tidal aspects of getting shipping in and out the ports of Bristol, Portishead, and Portbury.
Pilot Songs or Verses. The artist and sailor Alex Goodman alerted me of these. They are songs which contain information about pilot passages so it can be remembered.
Polder. An area of land on a low-lying tidal coast reclaimed from the sea by the construction of sea defences and dykes. Parts of the coast of the Netherlands are in effect a chain of polders. Often, they stand below sea-level at high tide and are thus vulnerable to extra high tides, storm surges and so on. As the sea is excluded, they form dry land suitable for agriculture and other uses. The dyke systems which drain them are fresh water, the saltier sea held back by sluices. One way of ‘rewilding’ coastal margins is to breach the seawall protecting an area of polder to allow the tides to turn it back to saltmarsh (see Unpoldering). In Bangladesh the low-lying coast has also been protected by polders. This has been effective, but also controversial, and some polders have been opened up to tidal influx again.
Polder Restoration. In something of a twist from polders being used to form land for societal use, polder restoration is a way of creating new salt marsh along tidal coastal margins which are under pressure or which are suitable for expansion. Fences of chestnut paling and brushwood are put in place on mud flats adjacent to saltmarsh. This slows the flows of tidal ebb and flow and the silt carried by the tide is deposited—thus building up new saltmarsh over time. A polder restoration project has occurred on the Rhymney Great Wharf in South Wales, UK.
Portbury Kiss. A large accidental black mark made on large ships as they pass through the Royal Portbury Port tidal lock gates at high tide, and rub against large rubber buffers.
Puja & Baix. The words for flood and ebb in the Catalan Atlas of 1375, one of the earliest tidal diagrams according to Howse; Some Early Tidal Diagrams.
Putcher. Also known as putcheons. Another form of a woven fish trap. They were conical shaped baskets, often made from willow and staked out in ranks on intertidal land. Their main purpose in the Severn Estuary was to catch salmon, and some other larger fish. They had a looser weave than a kype, thus letting small fish and shrimp pass through. They were generally set to facedown stream, thus catching fish on the incoming flood tide. See Fish Traps; Hedge Weir; Kype; Putcher; Putcheon; Putt; Stilbaai Tidal Fish Traps.
Putcheon. See Putcher.
Putt. See Kype.
Quarage. The rise in the level of a river caused by a high tide, which checks the regular downstream flow of a river and creates a buildup of water. This will happen on all the rivers which empty into tidal estuaries, except those which now stand behind barrages and dams; such as the rivers Ely and the Taff which are now faced with permanently high water at their mouths due to the Taff Barrage, Cardiff, Wales, UK.
Quarter Diurnal Tides. These are tides that have a rhythm of four high and four low waters in a single day (with roughly a 6-hour period between each turn). They are caused by local conditions rendering the more general tidal patterns of the deep oceans.
Real & Ecclesiastical Moon. In relation to the ‘age of the Moon’, there were some differences between the actual age of the Moon in its cycle and the age of the Moon in ecclesiastical calendars, this was important to know when using the religious calendars in relation to tidal prediction. Howse; Some Early Tidal Diagrams.
Reflux Of The Tide. This is from Daniel Defoe’s 1704 book The Storm, which describes the great storm of that year, using eye-witness testimony. It refers to the return of a rising tide. “It was, without doubt, a sad Spectacle to behold the poor Seamen walking too and fro upon the Sands, to view their Postures, and the Signals they made for help, which, by the Assistance of Glasses, was easily seen from the Shore. Here they had a few Hours Reprieve, but had neither present Refreshment, nor any hopes of Life, for they were sure to be all wash’d into another World at the Reflux of the Tide.”
Reversing Falls. A series of tidal rapids located in New Brunswick, Canada and Pembroke, Maine, where the river runs through a narrow gorge before emptying into the Bay of Fundy. The tides of the bay force the flow of water to reverse against the prevailing current when the tide is high. During the spring freshet, this reversal is often surpassed by the downstream volume of water. The rapids, or ‘falls,’ are created by a series of underwater ledges which roil the water in either direction, causing a navigational hazard. One must wait for the tide to lower in order to pass.
Roost. This is a term for regular areas of rough, fast flowing water, produced by tidal ebb and flow, often through channels and sounds. It is used by Rachel Carson in her essay The Sea: Wind, Sun and Moon. Here is another example; “Going west about from Kirkwall to Stromness will take about 3 1/2 hours at 8 knots. Leaving Stromness for Kirkwall is about the same as Stromness to Westray. During any westerly weather there is quite a roost out of Hoy Sound on the ebb.”
Rotary Current. A tidal current that flows continually, with the direction of flow changing 360° during a tidal cycle. It’s also called a rotary stream in some British hydrological terminology.
Rule of Twelfths, The. This is a way of predicting tidal heights in given locations between known high and low water. This is of use to those sailing, surfing and engaging with the sea in many ways. The total rise or fall of a tide (over 6 hours) is divided into twelve parts, with the water level changing by 1/12th in the 1st and 6th hours, 2/12ths in the 2nd and 5th hours, and 3/12ths in the 3rd and 4th hours.
Run of the Sea. A term for the flow, or current, in the sea when driven by tide and wind. Of obvious interest to navigation, fishing, swimming and other activities. As here, “[T]he run of sea one meets within the Crouch in heavy weather, under certain conditions of wind and tide, is really astonishing”. Francis B. Crooke; In Tidal Waters.
Salinity. Estuary waters are saline, or brackish—a mix of fresh and salt water. The ‘salinity gradient’ generally increases from the input source of fresh water to an estuary, such as a stream or river discharge, to the sea or ocean, where sea water dominates. Salinity is measured gravimetrically as parts per thousand (ppt). Within an estuary salinity levels are referred to as oligohaline (0.5–5.0 ppt), least saline; mesohaline (5.0–18.0 ppt); polyhaline (18.0–30.0 ppt), most saline. Near the open sea, estuarine waters may be euhaline, where salinity levels are the same as the ocean at more than 30.0 ppt. See Brackish.
Salmon Pool. This term applies to the Severn Estuary but maybe other places too. A salmon pool is a large pool of water left at low tide in the intertidal area. Salmon which find themselves trapped in the pool until the next high tide were often visible and catchable with nets such as handheld lave nets. C. M MacInnes and W. F. Whittard (eds.); Bristol and Its Adjoining Counties.
Salt Pans. Naturally occurring, salt pans are often small depressions in areas of saltmarsh which retain brackish water after being inundated by the tide whilst the land around then drains with the ebbing tide. Thus they are temporary tide pools. As they dry out the water becomes increasingly saline and, if they dry out completely this leaves salty residues on the lower surface. Salt pans are common and important features of many estuary saltmarsh areas.
Salt Ponds. These are, in essence, large tide pools; their size demanding the name pond rather than pool. One example, and source of the term for this glossary, is the Rachael Carson Salt Pond Preserve. This is a quarter of an acre pool that remains full of sea water as a tide retreats, located on the east coast of America in the state of Maine. Rachel Carson studied here, gathering some of the material for her book, The Edge of the Sea.
Salt Pruning (Tidal). Salt pruning refers to the killing of leaves on trees (and other plants) by contact with salt (sea) water. It is most commonly used in relation to blown sea spray affecting shoreline trees. However, where tree canopies come down to tidal waters on occasions one can see clearly defined high tide lines on the bottom edge of the canopy.
Salt Water Drovers. I saw this in relation to drovers who “worked with the tides in mustering the cattle as they move them from mainland Tasmania to Robbins Island”. There are many links between droving and tides as drovers knew of river mouth crossings, and crossings between mainland and islands, which were passable only at the lowest tides.
Salt Wedge. Salt water is heavier than fresh water, so, in some situations the fresh and salt water in an estuary will form distinct layers. A layer of fresh water might be flowing on top of a layer of salt water. The ebb and flow of the tide obviously affects how this is formed. The salt layer can be wedge-shaped as it lies in the bottom of the estuary channel that deepens out toward the sea. The fresh water layer on top might be a more consistent depth.
Salting(s). A salting is an area of grasslands which is regularly covered by salt water at high tide. They were common around many estuaries and tidally active places. Their grasses and other plants are adapted to tolerate the salt that the tides bring. Saltings were, and are, highly valued for livestock grazing. For example, saltmarsh raised lamb is considered to be a high value food product. In turn the grazing of the animals often helps maintain the important plant biodiversity and other species which depend on that. The grazing of stock on saltings often requires specialised management to ensure stock is not cut off and at risk from the highest tides.
Saros. Nineteen revolutions of the Sun with respect to the nodes of the Moon is equal in time to two hundred twenty-three lunations. This time, which is equivalent to eighteen years and eleven days, is called the ‘saros’. “At one time it was used in tidal work but is now practically obsolete.” From the Manual of Tidal Prediction.
Sea Lock. A lock on a canal, or navigable channel, where it meets the sea. The locks allowed for navigation between the sea and the canal system. Many of these locks were only navigable at high tide, and closed, and above the water line, at low tide. The sea lock of the Rolle Canal (aka the Torrington Canal) opening onto the Torridge Estuary, north Devon, England, is an example. It is now derelict. As many older, smaller ones will be in the UK. I have a lovely small engraving of the Sea Lock of the Bude Canal—drawn at low tide, from the foreshore.
Sea-Green. According to John R. Stilgoe in his book Shallow Water Dictionary, a sea-green is “ground overflowed by the sea in a spring tide”. He adds, “actual sea-greens lie just barely inland, just beyond the innermost wracklines, just beyond the last clumps of beach rose and the perfumeless sea lavender. There, in spring tides and hurricanes, the ocean intrudes, its seasonal swampings creating and maintaining odd wetland ecosystems”.
Sea-Mark. Again, according to Stilgoe, a sea-mark is some visible landmark (on land) which aids navigation, particularly useful when seeking a deep water channel, harbour or river mouth in difficult tidal waters. But also, he says, the term is used to identify “the utmost reach of the tide” which is marked on the foreshore by a tidal stand. He adds that this was, certainly, a Cornish (UK) usage. John R. Stilgoe, Shallow Water Dictionary: A Grounding in Estuary English. Seamarks is the title of a lengthy free-verse poem by St.-John Perse, French poet and Nobel Prize for Literature winner in 1960.
Seiches. These are fluctuations in bodies of water, e.g. lakes, which seem to be tides, resulting in rhythmic rise and fall of water and currents, but which are in fact caused by other forces, such a prevailing wind or varying barometric pressure seeing up enduring oscillations in bodies of water. They can either exacerbate or dampen tidal rise and fall. These are listed in some Japanese tide books. Source—Tampering with the Tides by F. Keith Dalton.
Sessile. Although not just applicable to tidal life, sessile—as in sessile animals, those fixed in one spot, like a limpet—are key features of tidal ecology. No one puts it better than the great Rachel Carson in The Sea Around Us. “The influence of the tide over the affairs of sea creatures as well as men may be seen all over the world. The billions upon billions of sessile animals, like oysters, mussels, and barnacles, owe their very existence to the sweep of the tides, which brings them the food which they are unable to go in search of”.
Sett of the Tide. Old English term for the direction of flow of the tide. Also just set of the tide. William Parkes, in his Report on The Severn Estuary, 1846, describes the set of the tide in various locations on the estuary.
Severn Pilot Cutter. A very fast, nimble sailing boat, mostly crewed by a master and a mate. They were used by the pilots of the Severn Estuary ports, who sailed out to the incoming ships to guide them into what were difficult navigations. These were self-employed pilots and got the work on a first-come first-served basis. Over time the craft became very highly refined for sailing in the tidal, fast-flowing waters of the estuary.
Severn Trow. A sort of sister vessel to the Severn Pilot Cutter. Trows were broad, flat-bottomed craft built to carry bulky cargoes such as bricks and coal. They were designed to be able to operate in relatively shallow water and also to withstand settling on sand and firm mud surfaces at low tide.
Shallow Water Zones. These are coastal areas which are vital for ocean ecology, as the shallowness of the water allows for sunlight penetration. This encourages the growth of phytoplankton and the related production of oxygen. They also can be important fish nurseries. Tidal rise and fall interacts in complex ways with shallow water zones, and they are considered to be important for supporting estuarine food webs, but in many estuaries, the water is not clear for the penetration of sunlight.
Shift Tides. This involves sighting the positions of the Sun and Moon using a sextant and cross-checking a nautical almanac to determine their location and phase in order to calculate the relative effect of coming tides on the navigation of the ship.
Shore Lark. This small lark is a rare winter visitor to the UK that feeds on coastal/tidal margins and tidal wracklines. Many migrating seabirds rely on intertidal habitat for their food, mating and nesting.
Slack Water/Slack-Tide. A short period of time at the turn of the tide between ebb and flood, and vice versa, when tidal waters are relatively still, neither rising or falling, or flowing with much force. ‘Slack-tide’ occurs in a lovely essay about the tidal Thames; Tale of a City: Secrets of a River; by Matthew Hollis; “Slack-tide is the river’s most hypnotic moment, an occurrence of such serenity that even the terns become temporarily becalmed.” See Water Slack; Stood-Still.
Slough. A slough is a tidal creek which is often part of a wider wetland/estuarine system. It seems to be a mostly American term. I first came across it in Jack London’s book Tales of the Fish Patrol. In that story, navigation up a slough is important but only possible when the tide is high. In America some sloughs are now part of important wetland conservation efforts, for example Elkhorn Slough, Monterey Bay, California.
Slub. A local dialect word common to Somerset for oaze, mud, or slimy wash, routinely deposited by the tides.
Snoor. An Orkney term mentioned in Sea Bean by Sally Huband, a snore is a tide that the observer is not sure is rising or falling. In some conditions, locations, and states of the tide, it can be hard to tell, at a glance, if the tide is rising or falling, or flowing up or down stream.
Snoring Tide (Snoring Ebb). The terms ‘snoring tide’ and ‘snoring ebb’ appears a number of times in Cooke; In Tidal Waters. It must mean a sleepy or gentle tide/ebb. I don’t know if it was just Cooke’s own phrase or one used more commonly.
Solstitial Tides. Tides occurring about the time of the solstices. Due to the Sun and the Moon having large declinations these tides are usually smaller in height than the average. From Manual of Tidal Prediction.
Southing of the Moon. According to Howse; Some Early Tidal Diagrams, this was a common phrase up until the 19th century. It was an expression trying to make sense of how the moon affected the tide in relation to navigation; the crossing of the Moon over the southern meridian being a marker for coming high tide.
Splash Zone. Intertidal areas are zoned in terms of habitats and the flora and fauna that occupy them. This is dictated by the extent to which they are inundated by higher water, or exposed to the air and sun at lower water. The splash zone is the very highest band of intertidal zoning. As the name implies, this area, just beyond the very margin of the sea at the highest tides, is affected by seawater splashes and spray. See Zonation.
Spoot Ebbs. In Orkney (Scotland), at the lowest tides, especially near the spring and autumn equinoxes, intertidal areas of sand are exposed where razor clams live. The clams are called spoots, so a spoot tide is one when they can be gathered. This is mentioned in Sea Bean by Sally Huband.
Spring Tide. Twice a month, at the times of the new Moon and the full Moon, the combined gravitational forces create larger than average variation known as spring tides, from the Old English word springan, meaning ‘a welling’. In other words, the low tide is at its lowest and the high tide is at its highest. They are the opposite of neap tides, when low and high tide are at a minimum.
Stand of the Tide. That period at which the tide ceases to rise or fall, vertically. Manual of Tidal Prediction.
Standing Waves. Waves that remain in the same position rather than progressive waves which advance. Bowers and Roberts, Tides. A Very Short Introduction. These can form in various conditions, but they occur commonly in tide races.
Stilbaai Tidal Fish Traps. “Ancient intertidal stonewall fish traps (Afrikaans: visvywers) that occur in various spots on the Western Cape coast of South Africa from Gansbaai to Mosselbaai. They consist of low walls of boulders and pebbles constructed across gullies or other suitable localities within the intertidal zone. Where no gullies or big rocks are present, complete artificial enclosures are built.” Fish traps were/are common in many, or most, tidal areas, as they provide a pretty easy way of catching fish. See Fish Traps.
Still-Stood. Nicholson, in Life Between the Tides, says that this is the ”wonderful phrase” Shakespeare used for the pause that happens at high tide. See Slackwater; Water Slack.
Stilling Well. Older tide gauges and recording machines relied on stilling wells. These are containers, such as a large enclosed pipe, with small inlets allowing sea water in. The purpose of a stilling well is to dampen the effects of waves or brief surges of water in order to measure the overall sea level, thus permitting the level in the well to rise and fall, reflecting the overall level of tide in the sea or river. A diagram of such a stilling well tide gauge can be seen in Philip L. Woodworth, Tidal Science Before and After Newton.
Stolen Tide (1). “A tide which approaches by stealth; particularly a local term for the high tides which creep up the gullies and marshes of coastal Lincolnshire, England.” Adapted from the Glossary in David Pugh, Changing Sea Levels: Effects of Tides, Weather and Climate.
Stolen Tide (2). This seems a different meaning to the above. Aldersey-Williams says that a stolen tide occurs when weather and wind conditions suppress the ebb of a flood tide and then the next high tide washes in bringing even higher levels. This can be a partial cause of tide related storm surges, such as the great flood of the North Sea in 1953.
Storm Tide. Perhaps more commonly termed storm surge. This is when a powerful storm combines with an incoming tide to create even higher water which can overtop sea defences and flood coastal areas. A storm tide devastated parts of the British and Dutch coasts in 1953. From an earlier time, W. G. Sebald writes in The Rings of Saturn, “On New Year’s Eve 1285, a storm tide devastated the lower town [Dunwich, Suffolk] and the portside so terribly that for months afterwards no one could tell where the land ended and the sea began”.
Sub-Littoral. A term for the very lowest areas of the overall intertidal zone, which are only exposed occasionally, at the very lowest reach of the lowest tides. See Zonation.
Subtidal (Zone). The margin of the sea from just below the low tide line to where the sea deepens. The higher margins of which might be very rarely exposed by an extreme low tide. This is usually a very rich zone in terms of marine biodiversity. Some creatures, such as some species of anemones, starfish and crabs are termed ‘subtidal’.
Swatch. Sometimes also swash, or swatchway. A relatively uncommon word for a deep channel, and/or a channel that is navigable at high tides. A swatch is marked on old maps at the mouth of the River Avon, Severn Estuary; Nore Swatch is named in some Thames Estuary sailing manuals.
Syrtes. In The Expedition of Humphry Clinker; by Tobias Smollett, 1771, The Solway Sands, which are passed over at low tide, causing danger to unwary travellers, are called Syrtes; as in “In crossing these treacherous Syrtes with a guide, we perceived a drowned horse…”. Syrtes, (singular Syrtis), is an archaic word for quicksand or bog, also used, as Smollett does, for intertidal mud and sandbanks. The term comes from the Gulf of Sidra in the Mediterranean Sea, off the northern coast of Libya. Historically it was known as the Great Sirte or Greater Syrtis. Although the tides in the Mediterranean are much lower than other seas, the sand banks created a danger for shipping. “The Syrtes Majors are unusually tidal and feature a strong 3–knot clockwise current at the rising tide, which then switches when the tide ebbs.”
Syzygian. Or sisigian, a term referring to syzygy (below) as in a ‘syzygian tide’.
Syzygy. The magical moment when the Earth, Moon, and Sun are all in alignment at the time of spring tides. It is this celestial alignment that creates the spring tides.
Tattle Tale. Light cord attached to a mooring line at two points a few inches apart with a slack section in between (resembling an inchworm) to indicate when the line is stretching from the ship’s rising with the tide. Only used in this way when moored to a fixed dock or pier on a flooding tide. Glossary of Nautical Terms. Not to be confused with the similar word telltales—the cloth or yarn ribbons attached to sails to indicate wind direction.
Tápholl (Taow-ful). An Irish word describing the calmness between two changes of falling or ebbing tide, an unsteady water when currents meet and are about to change direction. Magan; Sea Tamachotchi.
Tarrantacha. Another Irish word from Manchán’s Sea Tamagotchi that describes the loud noise and strong current that occurs when a spring tide is retreating. These currents can be very dangerous. The stones that are rolled around in the surf are also sometimes called tarrantacha. “You’d hear them banging against each other if you were near the shore”.
Tīd. The Anglo-Saxon word for time, seemingly linked to the word tide. Heard on the BBC radio programme; The Tides of the Staithe by Kevin Crossley-Holland.
Tidal Atlas (Tidal Stream Atlas). These are books of charts of tidal waters for navigation purposes. Mentioned by Aldersey-Williams who says, when describing navigating a family sea passage, “We also had a tidal atlas, a booklet with pages showing the same body of water at each hour before and after high water for a full tidal cycle of twelve hours”. Caroline Crampton also tells of her father using a tidal atlas when sailing in the Thames Estuary in her book, The Way to the Sea. Tidal stream atlases are still published for busy shipping areas like the English and Bristol Channels.
Tidal Breaking. The spin of the earth is, very gradually, getting slower. As J. White explains, this is caused by the dragging effect of the Moon on the Earth’s oceans which is acting as a break over deep time. This means that the times of day and night themselves will gradually change as the Earth continues to age.
Tidal Cultures. This is a WordPress blog which is run by Owain and in which this Glossary began. It also has: – a list and map of the ten highest tides in the world; a list of tide related art; a list of books about tides; a discussion of tides in literature, and more besides. It is also linked to a Facebook profile of the same name to which blog posts are shared and photos of Tide Team trips uploaded.
Tidal Establishment. This is a term for the repeating time of spring high tides in any given location. This more or less remains constant from year to year. Bowers and Roberts say that, for example, the tidal establishment at Juneau, occurs on the 13th of March at 1:30 pm.
Tidal Festivals. There are a small number of festivals around the world which are tidal in that they are staged to coincide with a high or low tide, and even use spaces of low tide. The tide, high tide, low tide etc. can be part of the programme on offer. Here are a few examples I know of. For a few years Stewart Ballard organised the Magnificent Severn Festival in Gloucestershire UK. This was held in a field by the tidal River Severn on the date of a high tide and the famous Severn Bore, as it passed the site, the bore was scheduled as part of the programme, along with bands and talks and other things etc. A similar tidal festival was held at Shirehampton Bristol on the River Avon as part of the Water City Bristol case study of the Towards Hydrocitizenship project. This was held at the delightful Lamplighters pub and Lamplighter Marsh on the banks of the River Avon and was staged between low water and high water at one of the highest tides of the year; 15 Oct 2016. A large tidal festival took place in Devonport, Tasmania in January 2017. Led by the Devonport Regional Gallery, a whole range of events and creations were staged, including in intertidal areas. Another example is ‘TideFest: The One Day Festival That Celebrates the Tidal Thames‘. Other tidal festivals occur under the heading Low Tide, High Tide, or even LowHigh Tide. Some internet searching will find them. One is the Low Tide Festival at Brighton UK in 1990 “we started and coordinated a tidal festival—LowTide—held on the Saturday in May with lowest tide” This was organised by RiverOcean.
Tidal Fill Pool. A term for a pool built to retain water after a high tide, often in a seaside resort, or on some beach or other, which is used for recreation. More commonly just called a tidal pool, or a marine lake. I came across this term when I spotted on a map, “The Old Tidal Fill Pool” on the foreshore at Portishead, near Bristol (UK). It is, sadly, derelict. There are pictures of this on the Severn Estuary Survey photographic blog.
Tidal Forest. Where coastal areas of trees are flooded by the sea and brackish water at high tide. Mangroves and Tidal Freshwater Forests are notable examples which are vital for both marine and terrestrial biodiversity. Such areas have been under pressure from coastal development and are now even more so by climate change.
Tidal Frame. The elevation range between the lowest and highest tides in a given location.
Tidal French. Like Estuary English, Tidal French is a unique dialect spoken in the coastal regions of Brittany and Normandy where huge tides occur. Its pronunciation is influenced by tidal rhythms and exhibits a number of distinctive phonetic features, including glottal stops, nasal vowels, and vowel mergers.
Tidal Lines. Lines on maps denoting the extent of the tide. These include ‘mean high water’, and ‘mean low water’ lines, and other variations. These are common on UK Ordnance Survey maps and their history is discussed in Brian Baily’s paper Ordnance Survey data collection and mapping of tidal features.
Tidal Islands. Simply places which are islands surrounded by sea at high tide, but connected to the land at low tide. There are a few famous examples in Britain and Europe (England), and Mount Saint-Michel (France). These have causeways raised above the intertidal ground to allow passage by foot or vehicle for longer until the tide rises above them.
Tidal Intrusion. This refers to the extent to which tidal water finds its way upstream in an estuary catchment at high tide. This can refer to the reach of the tide inland, and also the consequences of that, particularly degrees of salinity.
Tidal Prism. A tidal prism refers to “the volume of water that flows into an estuary or bay during flood tide.” Bowers and Roberts, Tides. A Very Short Introduction.
Tidal Rota. An early form of diagram which was intended to help explain and predict the rise and fall of the tides. A very beautiful example can be seen in Philip L. Woodworth; Tidal Science Before and After Newton.
Tidal Straining. “The action of a vertically sheared tidal flow on a horizontal density gradient. On the ebb tide in a well-mixed estuary, for example, the faster surface currents pull less dense water over denser water further out to sea creating stratification. The stratification will generally (but not inevitably) be destroyed when ebb turns to flood” Bowers and Roberts.
Tidal Train. In Victorian times (UK) enterprising tourism and rail/shipping companies ran ‘Tidal Trains’. These were trains destined to arrive at, and depart from, ports at high tide, in conjunction with ships run by the same company. Charles Dickens’s short story Out of Town is set in a fictional sea-side town in Kent (UK) which was brought into tourist based economic life by such trains—“The South-Eastern Company have brought Pavilionstone into such vogue, with their tidal trains and splendid steam-packets, that a new Pavilionstone is rising up.” There is a Tidal Train sculpture in Port Moody, British Columbia, by the sculptor Bruce Voyce.
Tidal Wake. A wake, as in ship’s wake, is commonly made by an object moving through water. Tidal wakes occur when tidal flows wash past a stationary object such as the pillars of a bridge or pier. I have made a film of a tidal wake flowing away downstream on an ebbing spring tide from Clevedon Pier, Somerset England.
Tidal Whirlpools. These are sea whirlpools caused by strong tidal flows interacting with each other, and with the local geography of the coast. Many are large and powerful and pose an obvious danger to navigation. These regularly form when the cycle of the tide dictates and are local ‘seamarks’ with names. They are often associated with spirits and folklore tales. The five largest renowned whirlpools are; Moskstraumen (Norway), Corryvreckan (Scotland), the Naruto Whirlpools (Japan), and the Mocinikosk or Old Sow and her smaller ‘piglets’ between Eastport, Maine and Deer Island in New Brunswick (USA/Canada).
Tidalectic. A play on words invented by Barbadian poet and historian Kamau Braithwaite. Tidalectics questions the terrestrial obsession with fixity, assuredness, and appropriation. Unbound by land-based modes of thinking and living, the term is reflective of the rhythmic fluidity of water and the persistent swelling and receding of tides. The movement of water backwards and forwards foregrounds diverse temporalities of oceanic space, delving into deeper layers of meaning, inviting a range of different readings and interpretations, as demonstrated in the exhibit and anthology, Tidalectics Imagining an Oceanic Worldview through Art and Science.
Tidalites. (Tidal Rhythmlites). These are geological deposits which are reckoned to show the layering of sediments by ancient tides. Aldersey-Williams says that there are examples in Big Cottonwood Canyon, Utah, where ‘the varying force of the tides is indicated by alternating light sandy layers left by strong tides able to transport sand and darker layers of mud deposited by weaker tides’.
Tide Books. Small books of yearly tables and other information are printed world-wide for coastal locations. They were designed to be carried in a pocket and were used by anyone whose work, and/or recreation, was affected by tides. Although online tide tables and apps for phones are now common, printed tide books are still very much in use. The yearly tide book for the Bristol Channel/Severn Estuary gives tide tables for eight locations, and has been published by Arrowsmith since 1835.
Tide Calendars. Similar to tide books but calendar-size, tide calendars depict graphic monthly marigrams of daily tidal levels and are a must for anyone exploring the coast.
Tide Crack. Discovered in the novel Lean Fall Stand by Jon McGregor, tide cracks appear in sea ice where tidal movement causes breaks in ice, particularly when sea ice connects to more solidly emplaced ice. There is a related term tide bending, where fields of sea-ice bend in relation to tidal rise and fall.
Tide Clocks & Watches. Most clocks and watches are, obviously, designed to keep track of time: the hours of the day, the minutes of the hour, the seconds of the minutes, and so on. But there are many examples of clocks and watches that were made for the purpose of telling the tide time. They could be set to tell the tide time at any given port or harbour. Some were spectacular clocks like grandfather clocks, and much-prized and valued possessions. A simple tide clock has just one hand which points to the height of the tide, with ‘high tide’ being where ’12’ is on a time clock, and ‘low tide’ at ‘6’. Many clocks were constructed that combined time keeping and tide time keeping. An example is a clock built by Roger Wearne, circa 1785, in Cornwall (UK). It was purchased by the St Aubyn family who lived on the tidal island of St. Michael’s Mount. This is now owned by the National Trust and can still be seen, and is still working! Tide clocks can still be purchased. But, to a large degree, in practical terms, apps on smartphones and computers now fulfil the same purpose.
Tide Gauge. A device to measure and record the changing height of sea level due to the tide. See Mareograph.
Tide Lock. See Sea Lock.
Tide Locking. This occurs when watercourses, drainage channels and even sewers, draining into a tidal water, cannot discharge into it due to a high tide. This can be a serious issue in relation to flooding. For example, in the 2007 floods on the lower River Severn (England), when extreme rainfall had fallen in the surrounding area, there were high tides on the river through Gloucester. So the local water courses could not discharge into the river for a few hours, adding to the rising floodwater in parts of the city.
Tide Mills (Fulling & Tucking Mills). A tide mill is one which has a water wheel operated by the flow of water held back from a high tide in a small reservoir controlled by sluices. Historically there were many located on coasts with high tidal ranges, often on inlets and river mouths. The relatively simple impoundment of water at high tide, which can then be slowly released to create power, meant that there was some flexibility when power was available. Given the need for renewable, sustainable energy and current interests in micro-power generation schemes, it seems surprising there is not more interest in working tide mills. Some mills were for grinding grain and other crops, other mills were Fulling or Tucking Mills. These were used in the processing of wool, driving large mechanical hammers which pounded the material. These were used in the processing of wool, driving large mechanical hammers which pounded the material.
Tide on the Make. A phrase meaning the tide rising.
Tide Over. This common phrase, to make do on little until better times, has a seafaring origin. According to America’s Coastal & Ocean Agency; “when there was no wind to fill the sails, sailors would float with the tide until the wind returned. They would ‘tide over.’”
Tide Prediction Machine. Many mechanical machines were built as part of efforts to accurately predict tide heights and times. David Edgar Cartwright; Tides; A Scientific History, reports that the first meaningful one was built in London in 1872. They became increasingly complex contraptions with many interconnecting pulleys, wheels, cogs, and wires, with differing components representing one of the forces that shape the tides, such as the Moon, Sun etc. The first generations of these were effectively analog computers or analog tide prediction machines.
Tide Ponds. On Ordnance Survey maps of the Severn Estuary, a number of ‘tide ponds’ are marked in the mud, sand and rocky intertidal areas. As one would imagine, these are ponds of brackish water left in place at low tide. They are of a size to be mappable features, so larger than, say, rock pools.
Tide Race. A place where strongly flooding or ebbing tides are forced through a narrow channel, or around a headland, thus making an extra fast, strong and turbulent flow. They often form a series of standing waves, and they are, for obvious reasons, a challenge to navigation and safe sea passage. There are many to be seen in the Severn Estuary and around the British coastline. See Standing Waves; Reversing Falls.
Tide Rip (Tiderip). Small waves formed on the surface of water by the meeting of opposing tidal currents or by a tidal current crossing an irregular bottom. Vertical oscillation, rather than progressive waves, is characteristic of tide rips.
Tide Staff. A tide gauge consisting of a vertical graduated pole from which the height of tide at any time can be read directly. Also called tide pole.
Tide Surveyor. “The Customs officer responsible for rummaging (searching) vessels anchored at port.” Graham Smith; Smuggling in the Bristol Channel 1700-1850.
Tide Surveyor Parlour. A room in one of the Watch Houses on the tidal River Avon near Pill, from where river traffic in and out of the Port of Bristol, and the tidal conditions, were observed by a tide surveyor. Part of the Pill Hobbler community and port business systems. Others may have existed elsewhere.
Tide Team. A group of friends who, a few times each year, go on a trip to explore some part of the Severn Estuary chosen by Owain, and find a nice pub. See Tidal Cultures.
Tide Warning Siren. Arneside, a village and civil parish in Cumbria (UK), which stands on the shore of Morecambe Bay, is famous for its fast-rising tides which very quickly cover wide sandy areas. At the higher tides, a siren is sounded to warn of the advance of the tide, the front which can be a swiftly moving tidal bore. I assume other such tide warning sirens might exist but have not found any yet.
Tide Watching. Tides are, undoubtedly, fascinating in many ways. Not least, they are fascinating visually on an hourly, daily and even momentary basis. And they are fascinating in the natures and cultures that move with the tide. So there are many accounts of ‘tide watching’. Some from shore, some from craft, just watching some or other tidal scene, for the tide itself, what it brings, and the local life it shapes. Here are two examples of ‘tide watching’. Edward Seago, in Tideline, says “This is why I find that ‘tide watching’ can be a dangerous game—it is far too indulgent for one of my temperament, which is probably the reason why it gives me so much pleasure”. “Sittin’ on the dock of the bay, Watchin’ the tide roll away” is, of course, a line from the popular music hit single; Sitting on The Dock of the Bay by Otis Redding.
Tide Water. Water that is moving with the tide. We have seen references to tide-water creeks and deep tide-water flows.
Tide-Hour of the Port. A term denoting the time when a rising tide makes a port navigable.
Tide-Swept. This is a technical term from marine ecology referring to habitats that are washed over by tidal currents. For example: “tide-swept sponge communities on shell/cobble substrates and bedrock in the upper reaches of the Daugleddau are exceptional in their diversity.”
Tide-Waiter. Sometimes written as tide waiter or tidewaiter, this was the title given to custom officers who would board ships entering and leaving ports and harbours to check their cargos in relation to whatever trade tariffs were in play at the time. I first saw this in The Mirror of the Sea by Joseph Conrad. There is an account online of a Tide-Waiter’s life called Tidewaiter Tate.
Tide-water Glacier. A term for a glacier that reaches all the way from inland to the ocean’s edge. Here, especially in places of high tidal range, such as the Northwest coast of North America, the rise and fall of the tide helps in the calving of icebergs. This term occurs on a number of occasions in John Muir’s last book; Travels in Alaska. One of the largest tidal glaciers in Alaska, the Muir Glacier, is named after him.
Tidemade. An object or feature that is made by the tide, i.e. revealed by a dropping or low tide. I found this in Maurice Griffiths, The First of the Tide; “In the hazy distance we could just make out the thin line that marked Whistable Street. A natural tidemade phenomenon, it forms a kind of finger of sand and gravel.”
Tiden. Seems to be the plural of tid and tide in Middle English. Also many other time related meanings in North European languages.
Tides Institute. Located in Eastport, Maine on the Passamaquoddy homelands and at the mouth of the Bay of Fundy, the Tides Institute and Museum of Art is a regional institution that shapes its perspective and programming through its rich tidal culture and unique geographical position to foster innovative cross-sector works, education and collaborations to increase the region’s vitality and wider connections.
Tidevann. This is the Norwegian word for tide. It means timewater. Which is rather lovely. I got this from a radio programme The Tidal Sense by the Norwegian artist Signe Lidén.
Tidewater. Tide-Water(s). I came across this term in Rachel Carson’s 1952 book Under the Sea-Wind. The term can mean waters of the sea mostly affected by the tide, and also sea water that floods over coastal margins at the higher tides. There is also a large region of the southern east coast of North America called ‘the tidewater’, as it is low-lying and thus affected by tides. This area was known for its tidewater accent and dialect. Tide-Waters occur on a number of occasions in John Muir’s last book; Travels in Alaska. As in: “this novel interruption of the channel is a bar of exceedingly hard resisting granite, over which the great glacier that once occupied it swept, without degrading it to the general level, and over which tide-waters now rush in and out with the violence of a mountain torrent.” See Flood Water.
Tiding. This was a practice in the Bay of Fundy area, Canada, by which saltmarsh was reclaimed to be agricultural land by building dikes and ditches which, over time, excluded the high tides from an area. This area would then slowly ‘sweeten’ as residual salt was leached away by rain and fresh water flows. This is described, with an illustration, in White’s book, Tides: The Science and Spirit of the Ocean.
Top of the Tide. A term for high water. In a video made by Black Rock Lath Net Heritage Fishery someone says they are sailing “on the top of the tide” as they pass under the Second Severn Bridge.
Topping Tide. Simply a spring tide that is high enough to over-top sea defences or the usual high water margin, thus flooding that which is beyond. Ann Lingard. The Story of the Solway.
Treece. A mark left on intertidal ground by bits of wood and other objects, as they are dragged, and then left stranded by the last ebbings of a falling tide (HG & OJ).
Tropic Tides. A term sometimes used to denote diurnal tides. It actually refers to the ‘trope’ or turning of the Sun and Moon in declination, but as these tides largely prevail in the tropics it has a certain appropriateness. Manual of Tidal Prediction.
Turves; Overhanging & Fallen. The seaward edges of many saltings, i.e. areas of saltmarsh pasture adjoining estuaries, are often short mud cliffs that fall away into the mudflats of the lower intertidal zone. Where this mud cliff is being eroded away by wave and current action, the turf of the grass layer, bound together by its roots, often overhangs the edge and then finally falls into the mudflat below. There they stay for a while as lumps of turf, being slowly broken down by each tide. (Turve is the plural of turf). See Peat Hag, which seems to mean the same thing.
Upriver Craft. On the Severn Estuary and the lowest tidal reaches of the river itself, as navigation conditions vary so markedly, for example, with upper tidal channels being shallower and narrower, and harbours smaller, some craft designs were adapted to be ‘upriver’ versions. Smylie depicts an ‘upriver punt’ used for fishing. The Gloucestershire Archives (undated) list a range of types of Severn trows, including ‘upriver trows’. I imagine this term might apply to other tidal places too.
Undular Bore. A tidal bore wave that is not breaking (as waves do on a beach) as it advances. Often small waves called whelps follow the leading front wave.
Unpoldering. A word for opening up polders to tidal rise and fall again. This is mostly to achieve rewilding of coastal areas, but it can also be used in modern urban coastal development where tidal creeks are carefully incorporated into new areas of coastal housing.
Vanishing Tide. “When the local semidiurnal and diurnal tidal constituents conspire to give several hours of relatively constant sea level.” Changing Sea Levels: Effects of Tides, Weather and Climate, David Pugh.
Wadden Academy. This is an independent scientific institute that acts as the primary knowledge broker for the highly tidal Wadden Sea Region. It was founded in 2008 and has headquarters in Leeuwarden, Netherlands, its core purpose is to bridge the gap between science, policy, and society to ensure the sustainable management of the Wadden Sea UNESCO World Heritage site.
Warth. Old version of Wharf.
Wadlopen. A Dutch word for ‘mud walking’, which is a common pastime during low tides on the Wadden Sea.
Watershed (Tidal). A watershed is commonly understood to be a margin or ridge that divides waters flowing in different directions on the land’s surface. In The Riddle of the Sands by Erskine Childers, the character Davis explains to his companion, and narrator of the book, Carruthers, that large intertidal sandflats of the Wadden Sea, where the action unfolds, will have their own watersheds. As they are never entirely flat, often domed, differing areas will drain in different directions on the ebb. This will make draining channels. These channels will fill in reverse at the tide rises again. The watersheds are the boundaries between these differing directions of flow.
Water Slack. This is how slack water is known on the North West American Seaboard. Bill Proctor and Yvonne Maximchuk, Full Moon, Flood Tide: Bill Proctor’s Raincoast,
Water Shot. When a Ship is moored neither across the tide, nor right up and down, but quartered between both. English Dialect Words of the Eighteenth Century; Nathaniel Bailey.
Weather-Going Tide. A tide which is flowing against the prevailing wind direction. This can make for choppy sea conditions. The phrase occurs on a number of occasions in Cooke; Tidal Waters. The height and time of high and low tide might be slightly altered from the predicted norm by such conditions.
Weather Tide. See above.
Wharf. A river or estuary bank once commonly used as a harbour. They still appear on maps of the Severn Estuary and, no doubt, many other tidal shorelines. Whale Wharf at Littleton-on-Severn was named as such when a huge sperm whale washed ashore there on a high tide in 1895.
Whelps. A train of secondary waves, typically of smaller amplitude, following the lead wave of a tidal bore, particularly of undular types. In France these waves are called éteules, which means stubble. Tides: A Very Short Introduction, Bowers and Roberts.
Whisket, Wisket. This is a name local to regions in England for shallow baskets made of split willow or hazel. They were light, shallow, sometimes oval bottomed, framed baskets. They were used for collecting the catches of Shankers (shrimpers) as depicted in the novel Seascraper by Benjamin Wood; and also, as another source says, catches of ‘lamperns’ (lampreys).
Wind-Over-Tide. Sea conditions created when a tidal current and wind run in opposite directions, leading to short, heavy seas.
Wolpehe. A Passamaquoddy (First Nations people, Bay of Fundy) word describing when the tide is favorable for launching a boat, digging clams, etc.; or a good tidal current for canoeing, etc.
Wrack. The tangle of debris, natural and man-made, found on the shore. An important part of coastal and intertidal ecology. See Wrack Line below.
Wrack Line. The line of debris left on the shore, marking the height of the previous high tide. On beaches and marshes, increasing tides keep picking up the previous debris and moving it up the shore, making it cumulatively bigger. Decreasing tides will leave a series of smaller wrack lines often in roughly parallel lines.
Young Tide. A newly rising tide. From the great novel Tarka the Otter by Henry Williamson.
Zonation. Given that, in many places, the intertidal zone is covered by the tides to differing heights and for differing lengths of time, the flora and fauna in situation have to adapt to, or cope with, differing periods of inundation by salt water, spray from braking waves, and also exposure to the air and maybe sun and maybe fresh water by rain of stream. This means that different organisms are adapted to live in differing zones in the overall intertidal area. These include seaweeds and crustaceans, and thus the zones can have differing textures and colours. Thus the zones can appear as strips running roughly parallel to the waterline and shore.
Select References
Hugh Aldersey-Williams, Tide: The Science and Law of the Greatest Force on Earth, 2016.
David George Bowers and Emyr Martyn Roberts. Tides: A Very Short Introduction. 2019.
Jack Hardisty. Estuaries: Monitoring and Modelling the Physical System, 2011.
Derek Howse. Some Early Tidal Diagrams. 1985; Lisboa: Instituto de Investigação Científica Tropical.
Sally Huband, Sea Bean: A Beach Comber’s Search for a Magical Charm, 2023
Manchán Magan. Sea Tamagotchi. 2020.
Peter H. Spectre. A Mariner’s Miscellany. 2005
John R. Stilgoe. Shallow Water Dictionary: A Grounding in Estuary English. 1990.
Johnathan White. Tides: The Science and Spirit of the Ocean. 2018.
Nautical Press. Manual of Tidal Prediction. 1950.
List Of Headings
Aestus
Age of the Moon
Age of the Tide
Anchialine Pools
Apflod
Aphelion
Apogean Tides
Back and Fill
Basket-Weir
Bawley
Besid-Neap
Big Run-Out
Black Tide
Blood Moon
Brackish
Breathings of the Moon
Brob
Cailleach
Cart Shanker, Shanker
Change Moon
Coming Tide
Cribbing / Crib (also Cribb, Cribbe)
Dark Moon
Dead Waters
Dead with the Tide
Dead-Low Water
Double Low Water / Double High Water
Drying Mooring / Drying Harbour
Drudging
Dutch Fair
Eagre
Ebb Current
Elver Tide
Emersion
Equinoctial Spring Tide
Establishment of the Port
Estero
Estuary English
Euryhaline
FFall, Tidal
Fill of the Tide
First of the Tide
Fish Trap / Weir
Flash-Lock
Flo and Esbe
Floating Harbour
Flood Current
Flood Gulls
Flow of the Moon
Foam Line
Foul Tide
Fresh, The
Freshes
Full Sea
Full Tide
Fyke Net (Fyke Netting)
Fylleflod
Going Tide
Golden Number of the Year
Gout
Gridiron
Half Tide
Half Tide Cross
Half Tide Passage
Half Tide Rocks
Head of the Tide. Tidehead
Heahflod
Hedge-Wier
Hydrogeographer
Inning
Lagging of the Tide
Last of the Tide
Lathe Net
Lee Tide (Leeward tide)
Lift of the Tide
Lively Waters
Low Tide Day(s)
Low Tide Walks
Low Water Channels
Low Water Landing Stage
Lower Shore
Lunitidal Interval
Make
Maretazo
Mareograph
Marigram
Mascaret
Mean (Lows; Highs, Springs)
Merse (Merses)
Middle Shore
Mud Horse
Mud-Gutting
Mud Patten
Mud Punt
Mudlark
Neap Tide
Negative (or Inverse) Estuary
Nepflod (Niptid)
New Cut
Normal Tidal Limit
Oaze
Oligohaline (Tidal) Marshes and Waters)
Overfalls. (Tidal Overfalls
Overtides
Palm Tide
Peat Hag
Perigean Tides
Pîl (also pill)
Pill Hobbler
Pilot Songs or Verses
Polder
Polder Restoration
Portbury Kiss
Puja and Baix
Putchers
Quarage
Real and Ecclesiastical Moon
Reflux of the Tide
Roost
Rotary Current
Rule of Twelfths, The
Run of the Sea
Salinity
Salmon Pool
Salt Pans
Salt Ponds
Salt Pruning (tidal)
Salt Water Drovers
Salt Wedge
Salting(s)
Sea Biscuits
Sea Lock
Sea-Green
Sea-Mark
Seiches
Sessile
Sett of the Tide
Severn Pilot Cutter
Severn Trow
Shallow Water Zones
Shift Tides
Shore Lark
Slack Water/Slack-Tide
Slough
Slub
Snoor
Snoring Tide (Snoring Ebb
Southing of the Moon
Splash Zone
Spoot Ebbs
Spring Tide
Standing Waves
Stilbaai Tidal Fish Traps
Still-Stood
Stilling Well
Stolen Tide (1)
Stolen Tide (2)
Storm Tide
Sub-Littoral
Subtidal
Swatch
Syrtes
Syzygian
Syzygy
Tattle Tale
Tīd
Tidal Atlas (Tidal Stream Atlas).
Tidal Breaking
Tidal Establishment
Tidal Festivals
Tidal Fill Pool
Tidal Frame
Tidal Intrusion
Tidal Lines
Tidal Prism
Tidal Rota
Tidal Straining
Tidal Train
Tidal Wake
Tidalites. (Tidal Rhythmlites)
Tide Book(s)
Tide Clocks (and Watches)
Tide Crack
Tide Gauge
Tide Lock
Tide Locking
Tide Mill
Tide on the Make
Tide Over
Tide Prediction Machine
Tide Pond
Tide Race
Tide Rip (Tiderip)
Tide Staff
Tide Surveyor
Tide Surveyor Parlour
Tide Warning Siren
Tide Watching
Tide-Hour of the Port
Tide-Swept
Tide-Waiter
Tide-Water Glacier
Tidemade
Tiden
Tidevann
Tidewater
Tiding
Top of the Tide
Topping Tide
Treece
Turves
Undular Bore
Unpoldering.
Upriver Craft
Vanishing Tide
Warth
Water Slack
Watershed (Tidal)
Weather Tide
Weather-Going Tide
Wharf
Whelps
Whisket,Wisket
Wind-Over-Tide
Wrack Line
Young Tide
Zonation
Tidal Cultures 
A wonderful compilation to celebrate our connections with the tide – thank you, Natasha
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Pingback: “Dutch Fair”, a kind of tidal market held at Great Yarmouth and maybe elsewhere added to our (Poetic) Tidal Glossary. “Dutch pipes, dried flounders, wooden shoes, apples, and gingerbread, are then offered for sale.” | Tidal Culture
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love this!
thank you!
Pingback: New words added to my Tidal Glossary: Maretazo and Syzyigian. | Tidal Cultures
Thank you for this blog post, I enjoyed it immensely. Many beautiful and lyrical words and phrases that would otherwise be lost to the mists of time.
Thanks!
Pingback: A number of new terms have been added to the Tidal Glossary recently | Tidal Cultures