Noc‐tur″nal (?), a. [L. nocturnalis, nocturnus, fr. nox, noctis, night. See Night, and cf. Nocturn.] 1. Of, pertaining to, done or occuring in, the night; as, nocturnal darkness, cries, expedition, etc.; — opposed to diurnal. Dryden.
2. Having a habit of seeking food or moving about at night; as, nocturnal birds and insects.