n. A mole or jetty carried out into the sea, to serve as an embankment to protect vessels from the open sea, to form a harbor, etc.n. A projecting quay, wharf, or other landing-place.n. One of the supports of the spans of a bridge, or any structure of similar character.n. In architecture or building:n. The solid support from which an arch springs. See first cut under arch.n. In medieval architecture, a large pillar or shaft; specifically, a compound or a square pillar.n. One of the solid parts between openings in a wall, such as doors and windows.n. The wall or post, of square or other form, to which a gate or door is hung.n. In a physical laboratory or observatory, a structure, generally of masonry, designed by its stability to prevent vibration in instruments which are supported by it.