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.
© Webster 1913.
Noc*tur"nal, n.
An instrument formerly used for taking the altitude of the stars, etc., at sea.
I. Watts.
© Webster 1913.