Half-moon

1.

The moon at the quarters, when half its disk appears illuminated.

2.

The shape of a half-moon; a crescent.

3.

An outwork composed of two faces, forming a salient angle whose gorge resembles a half-moon; -- now called a ravelin.

4.

A marine, sparoid, food fish of California (Caesiosoma Californiense). The body is ovate, blackish above, blue or gray below. Called also medialuna.