Lunule

Part of speech: noun (n.)

1. Anything crescent-shaped; a crescent-shaped part or mark; a lunula, a lune.

2. A lune. See Lune.

3. A small or narrow crescent.

4. A special area in front of the beak of many bivalve shells. It sometimes has the shape of a double crescent, but is oftener heart- shaped. See Illust. of Bivalve.