Noah Webster's New International Dictionary of the English Language

1. (n.) A flat tablet or ledge of any material set horizontally at a distance from the floor, to hold objects of use or ornament.

2. (n.) A sand bank in the sea, or a rock, or ledge of rocks, rendering the water shallow, and dangerous to ships.

3. (n.) A stratum lying in a very even manner; a flat, projecting layer of rock.

4. (n.) A piece of timber running the whole length of a vessel inside the timberheads.