Half″–moon′ (–mo͞on′), n. 1. The moon at the quarters, when half its disk appears illuminated.
2. The shape of a half-moon; a crescent.
See how in warlike muster they appear,
In rhombs, and wedges, and half-moons, and wings. Milton.
3. (Fort.) An outwork composed of two faces, forming a salient angle whose gorge resembles a half-moon; — now called a ravelin.
4. (Zoöl.) A marine, sparoid, food fish of California (Cæsiosoma Californiense). The body is ovate, blackish above, blue or gray below. Called also medialuna.