lunette

/luˈnɛt/

Other forms: lunettes

One type of lunette is a little half-moon shaped window that is part of a domed ceiling. You're more likely to see a lunette in a cathedral than in your own home.

During battles, military lunettes gave protection to troops taking cover behind them — they were temporary forts, curved into a protective shape and placed near but outside the main fortification. The curved window or opening also called a lunette is most often found in large structures like the Sistine Chapel and the Library of Congress. In Middle French, lunette means "little moon."

Definitions of lunette

1. noun

   oval or circular opening; to allow light into a dome or vault
   synonyms: fenestella

   type of:

   opening

   a vacant or unobstructed space that is man-made
2. noun

   temporary fortification like a detached bastion
   type of:

   fortification, munition

   defensive structure consisting of walls or mounds built around a stronghold to strengthen it