1.  lunette(n = noun.artifact) - temporary fortification like a detached bastion;
is a kind of fortification, munition

2.  lunette(n = noun.artifact) fenestella - oval or circular opening; to allow light into a dome or vault;
is a kind of opening
is a part of vault

1.  A fieldwork consisting of two faces, forming a salient angle, and two parallel flanks. See Bastion. [1913 Webster]

2.  A half horseshoe, which lacks the sponge. [1913 Webster]

3.  A kind of watch crystal which is more than ordinarily flattened in the center; also, a species of convexoconcave lens for spectacles. [1913 Webster]

4.  A piece of felt to cover the eye of a vicious horse. [1913 Webster]

5.  Any surface of semicircular or segmental form; especially, the piece of wall between the curves of a vault and its springing line. [1913 Webster]

6.  An iron shoe at the end of the stock of a gun carriage. [1913 Webster]

lunette, n.
1 an arched aperture in a domed ceiling to admit light.
2 a crescent-shaped or semicircular space or alcove which contains a painting, statue, etc.
3 a watch-glass of flattened shape.
4 a ring through which a hook is placed to attach a vehicle to the vehicle towing it.
5 a temporary fortification with two faces forming a salient angle, and two flanks.
6 RC Ch. a holder for the consecrated host in a monstrance.

Etymology:
F, dimin. of lune (see LUNE)