Causeway

Causeway

The Hindenburgdamm Rail Causeway across the Wadden Sea to the island of Sylt in Schleswig-Holstein, Germany
Ancestor	None. (See Ford (crossing))
Related	None. (See Step-stone bridge)
Descendant	None. (See Viaduct)
Carries	Traffic, Rail
Material	Concrete, Masonry, Earth-fill
Movable	No
Design effort	medium
Falsework required	No

In modern usage, a causeway is a road or railway on top an embankment usually across a broad body of water or wetland.

The Welsh word 'cawsai' translates directly to the English word 'causeway'; it is possible that, with Welsh being a lineal linguistic descendant of the original native British tongues, the English word derives from the Welsh.

When first used, the word appeared in a form such as "causey way" making clear its derivation from the earlier form "causey". This word seems to have come from the same source by two different routes. It derives ultimately, from the Latin for heel, calx, and most likely comes from the trampling technique to consolidate earthworks.

Anciently, the construction was trodden down, one layer at a time, often by slaves or flocks of sheep. Today, this work is done by machines. The same technique would have been used for road embankments, raised river banks, sea banks and fortification earthworks. (The layers, though not the trampling action, can be seen in the Bayeux Tapestry: Building Hastings Castle.)

The second derivation route is simply the hard, trodden surface of a path. The name by this route came to be applied to a firmly-surfaced road. It is now little-used except in dialect and in the names of roads which were originally notable for their solidly-made surface. The 1911 Encyclopædia Britannica states "causey, a mound or dam, which is derived, through the Norman-French caucie (cf. modern chaussée), from the late Latin via calciata, a road stamped firm with the feet (calcare, to tread)."

The word is comparable in both meanings with the French chaussée, from a form of which it reached English by way of Norman French. The French adjective, chaussée, carries the meaning of having been given a hardened surface, and is used to mean either paved or shod. As a noun chaussée is used on the one hand for a metalled carriageway, and on the other for an embankment with or without a road. Other languages have a noun with similar dual meaning. In Welsh, it is sarn. The Welsh is relevant here, as it also has a verb, sarnu, meaning to trample. The trampling and ramming technique for consolidating earthworks was used in fortifications and there is a comparable, outmoded form of wall construction technique, used in such work and known as pisé, a word derived not from trampling but from ramming or tamping.