Meaning

adjective belonging to or active during the night

adjective of or relating to or occurring in the night

originFrom Middle French nocturnal, from Latin nocturnālis (“nocturnal”), from Latin nocturnus (“nocturnal”), from Latin nox (“night”), from Proto-Indo-European *nókʷts (“night”). Cognates include Ancient Greek νύξ (núx), Sanskrit नक्ति (nákti), Old English niht (English night) and Proto-Slavic *noťь.

Etymology from Wiktionary, CC BY-SA 3.0