from
The Collaborative International Dictionary of English v.0.48
Half-moon \Half"-moon`\ (-m[=oo]n`), n.
1. The moon at the quarters, when half its disk appears
illuminated.
[1913 Webster]
2. The shape of a half-moon; a crescent.
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See how in warlike muster they appear,
In rhombs, and wedges, and half-moons, and wings.
--Milton.
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3. (Fort.) An outwork composed of two faces, forming a
salient angle whose gorge resembles a half-moon; -- now
called a {ravelin}.
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4. (Zool.) A marine, sparoid, food fish of California
({C[ae]siosoma Californiense}). The body is ovate,
blackish above, blue or gray below. Called also
{medialuna}.
[1913 Webster]