\Buoy\, n. [D. boei buoy, fetter, fr. OF. boie, buie,
chain, fetter, F. bou['e]e 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.

\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. --Burke.
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. --Darwin.

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