An Etymological Dictionary of the German Language/Luchs
Luchs, m., ‘lynx,’ from the equiv. MidHG. and OHG. luhs, m.; corresponding to OSax. lox, Du. losch, AS. lox, m. The s of this OTeut. stem is a suffix, as in Fuchs; hence Swed. lô (Goth. *laúhô), and in the non-Teut. languages Lith. lúszis, Gr. λυγκ-, ‘lynx.’ It is probably related to the root luh in Licht (OIc. ljós, ‘light,’ AS. lîxan, ‘to give light’), since the sharp, gleaming eyes of the lynx may have given rise to the name.