ETYM Dutch boei buoy, fetter, from Old Fren. boie, buie, chain, fetter, French bouée a buoy, from Latin boia.
(Homonym: boy).
Bright-colored; a float attached by rope to the seabed to mark channels in a harbor or underwater hazards.
Floating object used to mark channels for shipping or warn of hazards to navigation. Buoys come in different shapes, such as a pole (spar buoy), cylinder (automobile buoy), and cone (nun buoy). Light buoys carry a small tower surmounted by a flashing lantern, and bell buoys house a bell, which rings as the buoy moves up and down with the waves. Mooring buoys are heavy and have a ring on top to which a ship can be tied.

1. To float on the surface of water.
2. To keep afloat:; SYN. buoy up.
3. To mark with a buoy.