From Middle French nocturnal, from Latin nocturnus (“nocturnal, nightly”), 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.
- (of a person, creature, group, or species) Primarily active during the night.
- nocturnal birds
- (of an occurrence) Taking place at night, nightly.
2013 January 1, Paul Bartel, Ashli Moore, “Avian Migration: The Ultimate Red-Eye Flight”, in American Scientist, volume 101, number 1, page 47–48:
- Many of these classic methods are still used, with some modern improvements. For example, with the aid of special microphones and automated sound detection software, ornithologists recently reported […] that pine siskins (Spinus pinus) undergo an irregular, nomadic type of nocturnal migration.
- a suspicious nocturnal outing
nocturnal (plural nocturnals)
- A person or creature that is active at night.
- (historical) A device for telling the time at night, rather like a sundial but read according to the stars.