Etymology

Noun

1. A small opening in a vaulted roof of a circular or crescent shape.
2. A crescent-shaped recess or void in the space above a window or door.
3. A field work consisting of two projecting faces forming a wedge each of which extends from one of two parallel flanks.
4. (the shape of) a crescent-shaped dune.
5. Goggles for swimming under water.
6. A crescent-shaped clip for holding the host upright when exposed in the monstrance.

Noun

1. telescope (specifically a refracting telescope and not a reflecting telescope, which is télescope)
2. lunette
3. toilet seat