wĺ̥kʷos

The reconstruction *wĺ̥kʷos ("wolf") exemplifies the regularity of PIE sound correspondences across all major branches. The initial *w- is preserved in Germanic and Balto-Slavic, lost in Greek and Latin (where *wl- > l-), and preserved in Sanskrit (as v-). Latin lupus (from earlier *lukʷos, with assimilation of the labialised velar to a labial) shows one of the more complex phonological developments. The shift *wĺ̥kʷos > *lukʷos > lupus involves both the loss of initial *w- before a liquid and the progressive assimilation of *kʷ to p before the labial vowel u. From lupus derive lupine, Lupercalia, and the medical term lupus. Greek lýkos (λύκος) shows the regular loss of initial *w- (digamma) and the simplification of the labialised velar. The extensive mythology of the wolf in Greek culture is reflected in the name Lykaon, the concept of lycanthropy (λυκανθρωπία, "wolf-man transformation"), and the Lykeion (the grove of the wolf, where Aristotle taught—whence "lyceum"). Sanskrit vŕ̥ka preserves the initial *w- as v- and shows the regular satem treatment. The word appears in the R̥gveda in both literal and metaphorical contexts. Proto-Germanic *wulfaz yields English wolf, German Wolf, Old Norse úlfr, and Gothic wulfs. The *-f- rather than expected *-kʷ- or *-p- has been debated; it may reflect an early dialectal variant or a taboo deformation (a common phenomenon in words for feared animals). The cultural significance of the wolf in PIE society is attested by the frequency of wolf-related personal names across branches: Germanic Wulf-, Adolf, Rudolf; Greek Lyko-; Sanskrit Vŕ̥ka-. The warrior-wolf complex, in which young warriors identify with wolves, is attested in Germanic, Italic, and Indo-Iranian traditions, suggesting a PIE cultural institution.