lynx (n.) Look up lynx at Dictionary.com
mid-14c., from Latin lynx (source of Spanish, Portuguese, Italian lince), from Greek lyngz, perhaps from PIE *leuk- "light" (see light (n.)), in reference to its gleaming eyes or its ability to see in the dark.
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]
Compare Lithuanian luzzis, Old High German luhs, German luchs, Old English lox, Dutch los, Swedish lo "lynx."