Crescent-shaped window

I believe the answer is:
(Other definitions for lunette that I've seen before include "Towing-ring; crescent shape" , "Crescent-shaped space" , "Semi-circular alcove" , "Arched aperture" , "fortification" .)
I believe the answer is:
(Other definitions for lunette that I've seen before include "Towing-ring; crescent shape" , "Crescent-shaped space" , "Semi-circular alcove" , "Arched aperture" , "fortification" .)