lynx (n.) Look up lynx at
moderate-sized wildcat with a short tail, penciled ears, more or less spotted fur, and 28 teeth, inhabiting Eurasia, Africa, and North America; mid-14c., from Latin lynx (source of Spanish, Portuguese, Italian lince), from Greek lyngx, an old name of the lynx found also in Armenian, Germanic, and Balto-Slavic, though often transformed or altered. Often linked to PIE *leuk- "light" (see light (n.)), in reference to its gleaming eyes or its ability to see in the dark, but there are phonetic problems with that and Beekes suggests a loan from a non-IE substrate language.
If that men hadden eyghen of a beeste that highte lynx, so that the lokynge of folk myghte percen thurw the thynges that withstonden it. [Chaucer's "Boethius," c. 1380]
Cognates probably are Lithuanian lušis "lynx," Old High German luhs, German luchs, Old English lox, Dutch los, Swedish lo, Armenian lusanunk'.