Cognate with Latvian kūnis (“pupa (of an insect); body”), with further origin uncertain: * Charpentier and Fraenkel derive the word from Proto-Indo-European *(s)kewH- (“to cover”), with Fraenkel comparing the long vowel in Lithuanian to that of Ancient Greek σκῦτος (skûtos, “skin, hide”) in particular. * Another theory takes the word as a derivative from the verb káuti (“to beat, strike”), where the noun's original sense was "(well-hewn) body", in which case from Proto-Balto-Slavic *káuˀtei, from Proto-Indo-European *kowh₂, from *kewh₂- (“to strike”). * Bruckner compares the word to Proto-Slavic *kъnъ (“trunk”) (whence Polish do cna (“totally, completely”)); however, the long ū in the Lithuanian term makes this phonetically doubtful.