jetty: [15] A jetty is a structure that literally projects or is ‘thrown’ out beyond what surrounds it. The word was borrowed from Old French jetee, where it originated as the past participle of the verb jeter ‘throw’ (source also of English jet, as in ‘jet engine’). It was used originally both for a structure jutting out into a body of water, and for a projecting upper storey of a house, of which the latter now survives only as a technical term in architectural history. => jet[jetty etymology, jetty origin, 英语词源]