Lu"nule (?), n. [F., fr. L. lunula, dim. of luna moon.]
Anything crescent-shaped; a crescent-shaped part or mark; a lunula, a lune.
A lune. See Lune.
3. Zool. (a)
A small or narrow crescent.
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.
© Webster 1913.