\Lu*nette"\, n. [F., dim. of lune moon, L. luna. See
{Lune} a crescent.]
1. (Fort.) A fieldwork consisting of two faces, forming a
   salient angle, and two parallel flanks. See {Bastion}.
2. (Far.) A half horseshoe, which wants the sponge.
3. A kind of watch crystal which is more than ordinarily
   flattened in the center; also, a species of convexoconcave
   lens for spectacles.
4. A piece of felt to cover the eye of a vicious horse.
5. (Arch.) Any surface of semicircular or segmental form;
   especially, the piece of wall between the curves of a
   vault and its springing line.
6. An iron shoe at the end of the stock of a gun carriage.
{Lunette window} (Arch.), a window which fills or partly
   fills a lunette.