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. [ 1913 Webster ]

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 buoy 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. [ 1913 Webster ]

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. [ 1913 Webster ]

2. To support or sustain; to preserve from sinking into ruin or despondency. [ 1913 Webster ]

Those old prejudices, which buoy up the ponderous mass of his nobility, wealth, and title. Burke. [ 1913 Webster ]

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. [ 1913 Webster ]

Not one rock near the surface was discovered which was not buoyed by this floating weed. Darwin. [ 1913 Webster ]

v. i. To float; to rise like a buoy. “Rising merit will buoy up at last.” Pope. [ 1913 Webster ]

n. Buoys, taken collectively; a series of buoys, as for the guidance of vessels into or out of port; the providing of buoys. [ 1913 Webster ]

n. Buoyancy. [ R. ] [ 1913 Webster ]

n.; pl. Buoyancies 1. The property of floating on the surface of a liquid, or in a fluid, as in the atmosphere; specific lightness, which is inversely as the weight compared with that of an equal volume of water. [ 1913 Webster ]

2. (Physics) The upward pressure exerted upon a floating body by a fluid, which is equal to the weight of the body; hence, also, the weight of a floating body, as measured by the volume of fluid displaced. [ 1913 Webster ]

Such are buoyancies or displacements of the different classes of her majesty's ships. Eng. Cyc. [ 1913 Webster ]

3. Cheerfulness; vivacity; liveliness; sprightliness; -- the opposite of heaviness; as, buoyancy of spirits. [ 1913 Webster ]

a. [ From Buoy, v. t. & i. ] 1. Having the quality of rising or floating in a fluid; tending to rise or float; as, iron is buoyant in mercury. “Buoyant on the flood.” Pope. [ 1913 Webster ]

2. Bearing up, as a fluid; sustaining another body by being specifically heavier. [ 1913 Webster ]

The water under me was buoyant. Dryden. [ 1913 Webster ]

3. Light-hearted; vivacious; cheerful; as, a buoyant disposition; buoyant spirits. -- Buoy"ant*ly, adv. [1913 Webster]

See under Buoy, n. [ 1913 Webster ]

n. The act of buoying up; uplifting. [ R. ] Coleridge. [ 1913 Webster ]