(n.) Any structure or contrivance, as a mole, or a wall at the mouth of a harbor, to break the force of waves, and afford protection from their violence.

abutment anchorage anchorage ground arc-boutant arch dam backstop bamboo curtain bank bar barrage barrier basin beam bear-trap dam beaver dam berth bill boom breastwork brick wall buffer bulkhead bulwark buttress buttress pier buttressing cape chersonese cofferdam coral reef dam defense delta dike ditch dock dockage dockyard dry dock earthwork embankment fence flying buttress foreland gate gravity dam groin hanging buttress harbor harborage haven head headland hook hydraulic-fill dam iron curtain jam jetty jutty landing landing place landing stage leaping weir levee logjam marina milldam moat mole moorings mound mull naze ness parapet peninsula pier pier buttress point port portcullis promontory protected anchorage quay rampart reef retaining wall road roadblock roads roadstead rock-fill dam sandspit seaport seawall shipyard shoulder shutter dam slip spit spur stone wall tongue wall weir wharf wicket dam work