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.
Curved or flat heart-shaped area on the outside of a bivalve shell along the hinge line and anterior to the umbones.
the crescent-shaped area at the base of the human fingernail
Crescent-shaped spot on wing
A crescent shaped mark. Like the moon, lunar.
Cutlicular thickening at base of claws in certain tardigrades, normally half-moon in shape.