n. A float fixed at a certain place to show the position of objects beneath the water, as shoals, rocks, etc., to mark out a channel, and the liken. A buoyant object designed to be thrown from a vessel to assist a person who has fallen into the water to keep himself afloat; a life-buoy.To support by a buoy or as by a buoy; keep afloat in a fluid; bear up or keep from sinking in a fluid, as in water or air: generally with up.Figuratively, to support or sustain in any sense; especially, to sustain mentally; keep from falling into despondency or discouragement: generally with up.To fix buoys in as a direction to mariners: as, to buoy or to buoy off a channel.To float; rise by reason of lightness.