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 root *leuk- "light, brightness," 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 lūšis "lynx," Old High German luhs, German luchs, Old English lox, Dutch los, Swedish lo, Armenian lusanunk'. The dim northern constellation was added in 1687 by Johannes Hevelius. Lyncean "pertaining to a lynx" (from Greek lynkeios) is attested from 1630s.