Why this word is great
LUNULE — [Noun] A small, crescent-shaped mark or anatomical structure, such as the pale arch at the base of a fingernail or a defined feature on a bivalve shell. From the French *lunule*, from the Latin *lūnula*, a diminutive of *lūna* ("moon"). Unlike "lunula," which specifically denotes the fingernail's whitish arc, or "crescent," which broadly evokes any moonlike curve, a lunule is the taxonomist's or anatomist's precise term for a fixed, minor curvature. It is the opalescent parenthesis at your thumbnail's root, the precise fossa on the hinge-plate of a clam, or the faint, fossilized smile pressed into stone by an ancient brachiopod—a collection of small, borrowed moons, each a private and fading satellite to its host.