From Proto-Indo-European *kuH-l-, zero-grade without s-mobile form of *(s)kewH- (“to cover”). Cognates include Old Irish cúl (“bottom”), Lithuanian kẽvalas (“skin, cover”) and indirectly Old English hȳd (English hide). Related to obscūrus (“dark, obscure”) and cutis (“hide”).
cūlus (genitive cūlī); m, second declension
- (vulgar) The anus, arse; the posterior, buttocks
- Catullus poem 97 (translation adapted by H.J.Walker, which can be viewed here)
- Non (ita me di ament) quicquam referre putaui,
- utrumne os an culum olfacerem Aemilio.
- I swear by the gods I didn't think it mattered one straw,
- whether I sniffed Aemilius's head or his arse.