Buoy

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.
3. 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.
4. To float; to rise like a buoy.
5. To fix buoys to; to mark by a buoy or by buoys; as, to buoy an anchor; to buoy or buoy off a channel.