lunette

1. (architecture) A small opening in a vaulted roof of a circular or crescent shape.Examples: "Nanny Broome was looking up at the outer wall. Just under the ceiling there were three lunette windows, heavily barred and blacked out in the normal way by centuries of grime."; "Next came the semi-landing with the lunette window, and here the door opened under the pressure of a single finger, and with a sigh and creak."

2. (architecture) A crescent-shaped recess or void in the space above a window or door.Examples: "The decoration of a lunette discovered in the Duomo of Pistoia in the 1950s, which represents Christ blessing and Saints James and John, all bust-length, constitutes a more remarkable and stylistically more advanced approach to painting."

3. (obsolete) An image or other representation of a crescent moon.Examples: "The lesser portions of the tablet has over this Mithras, a lunette or symbol of the moon, who, according to Porphyry's comment, is the queen of generation and as such was denominated by the ancients both a bee and a bull [...]."obsolete

4. (fortifications) A field work consisting of two projecting faces forming a wedge each of which extends from one of two parallel flanks.Examples: "This Lunette, as we have seen, was confronted, and even in siege-form "approached", by a part of Canrobert's army [...]."; "In mid-December [...], the French succeeded in storming the half-ruined outwork of the St Laurent lunette and advancing to a position immediately beneath the walls with their breaching batteries."

5. (Christianity) A luna: a crescent-shaped receptacle, often glass, for holding the (consecrated) host (the bread of communion) upright when exposed in the monstrance.Examples: "On those occasions when lunettes, custodia and monstrances are used, the sacristan needs to be sure that the lunette fits into the given monstrance, that the host fits into the lunette, and that the host is put out before Mass for consecration."

6. (geology) A type of crescent-shaped dune blown up along a lake basin, especially in dry areas of Australia.Examples: "Sticking out of a crescent-shaped sand ridge of a type known as a lunette were some human bones."; "These lunettes are relicts of a Late Pleistocene deflationary period, when the lacustrine hydrology changed from perennial water-filled lakes to desiccated mudflats."