n. [ F., fr. L. lunula, dim. of luna moon. ] 1. (Anat.) Anything crescent-shaped; a crescent-shaped part or mark; a lunula; a lune. [ 1913 Webster ]

2. (Chem.) A lune. See Lune. [ 1913 Webster ]

3. (Zool.) (a) A small or narrow crescent. (b) 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. [ 1913 Webster ]

n. [ Dim. of lunule. ] (Zool.) A small spot, shaped like a half-moon or crescent; as, the lunulet on the wings of many insects. [ 1913 Webster ]