brille
noun
bril·le ˈbri-lə 
plural brilles
: a transparent, disc-shaped, immobile scale that covers the eye of most snakes and geckos
Like snakes, geckos can't close their eyes, which are protected by a transparent scale, or brille (from the German for spectacles) that is regularly shed and replaced along with the skin.
Richard Milner, Natural History, November 2000
Richard Milner, Natural History, November 2000
Word History
Etymology
borrowed from German Brille, literally, "spectacle, eyeglass," going back to Middle High German berille, barille (masculine singular) "beryl, rock crystal," (used in reliquaries, monstrances, etc., to magnify objects), borrowed from Latin bēryllus beryl
First Known Use
1903, in the meaning defined above