The Old English version of wharf was hweorf. It referred to any substantial structure of wood or stone built along the water’s edge so that ships could pull up alongside, and it was in use as early as 1067. Pier, quay, mole, breakwater, and seawall are all historically linked. Originally, a pier extended out into the water, as opposed to a wharf, which didn’t. Its purpose was also to facilitate the loading and unloading of ships, and also perhaps partly to form or protect a harbor. The word pier was in use by 1390. By the nineteenth century, it tended to refer to raised structures built on columns, still for the purposes of docking, but also for promenading and for fishing. A mole—the word derives from the Latin moles, or “mass”—is a much larger structure, usually of stone, built out into the water, often in a circular or enclosing shape. One could load or unload ships on moles, but their essential function was to serve as a breakwater, which created an artificial harbor. The word came into use, probably from France, in the sixteenth century, and it came to mean not only the breakwater but also the harbor it enclosed. A quay, from the French quai, originally referred to an artificial bank or landing place that either lay parallel to or projected into navigable waters for the loading and unloading of ships. A definition of 1696 describes a quay (pronounced “key”) as “a broad, paved space upon the shore of a river, a haven or port for the unloading of goods,” which would seem to make it a synonym for wharf, and it is. Breakwater, though a thoroughly Anglo-Saxon combination, does not show up in the written record until the eighteenth century, where it is treated as a synonym for jetty and seems to mean distinctly a maritime structure built to protect land from the action of waves. Seawall in its earliest Old English use referred to a sea cliff; by the fifteenth century it had come to mean a breakwater.

Robert Hass