Black's Law Dictionary (2nd edition)dictionaries

Buoy

In maritime law. A piece of wood or cork, or a barrel, raft, or other thlng, made secure and floating upon a stream or bay, intended as a guide and warning to mariners, by marking a spot where the water is shallow, or where there is a reef or other danger to navigation, or to murk the course of a devious channel

Source: Black's Law Dictionary 2nd Ed (1910)