lu·nette /luˈnɛt/
  眼鏡堡,弦月窗,半圓壁
  Lu·nette n.
  1. Fort. A fieldwork consisting of two faces, forming a salient angle, and two parallel flanks. See Bastion.
  2. Far. A half horseshoe, which lacks the sponge.
  3. A kind of watch crystal which is more than ordinarily flattened in the center; also, a species of convexoconcave lens for spectacles.
  4. A piece of felt to cover the eye of a vicious horse.
  5. Arch. Any surface of semicircular or segmental form; especially, the piece of wall between the curves of a vault and its springing line.
  6. An iron shoe at the end of the stock of a gun carriage.
  Lunette window Arch., a window which fills or partly fills a lunette.
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  lunette
       n 1: temporary fortification like a detached bastion
       2: oval or circular opening; to allow light into a dome or
          vault [syn: fenestella]