Buoy, v. t. [imp. & p. p. Buoyed (?); p. pr. & vb. n. Buoying.] 1. To keep from sinking in a fluid, as in water or air; to keep afloat; -- with up.

2. To support or sustain; to preserve from sinking into ruin or despondency.

Those old prejudices, which buoy up the ponderous mass of his nobility, wealth, and title.

3. To fix buoys to; to mark by a buoy or by buoys; as, to buoy an anchor; to buoy or buoy off a channel.

Not one rock near the surface was discovered which was not buoyed by this floating weed.

Buoy, v. i. To float; to rise like a buoy. "Rising merit will buoy up at last." Pope.

Buoy (?), n. [D. boei buoy, fetter, fr. OF. boie, buie, chain, fetter, F. bouée a buoy, from L. boia. "Boiae genus vinculorum tam ferreae quam ligneae." Festus. So called because chained to its place.] (Naut.) A float; esp. a floating object moored to the bottom, to mark a channel or to point out the position of something beneath the water, as an anchor, shoal, rock, etc.

Anchor buoy, a buoy attached to, or marking the position of, an anchor. -- Bell buoy, a large buoy on which a bell is mounted, to be rung by the motion of the waves. -- Breeches buoy. See under Breeches. -- Cable buoy, an empty cask employed to buoy up the cable in rocky anchorage. -- Can buoy, a hollow buoy made of sheet or boiler iron, usually conical or pear-shaped. -- Life buoy, a float intended to support persons who have fallen into the water, until a boat can be dispatched to save them. -- Nut or Nun buoy, a buoy large in the middle, and tapering nearly to a point at each end. -- To stream the buoy, to let the anchor buoy fall by the ship's side into the water, before letting go the anchor. -- Whistling buoy, a buoy fitted with a whistle that is blown by the action of the waves.