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. [ 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. 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 ]