·noun An instrument formerly used for taking the altitude of the stars, ·etc., at sea.
II. Nocturnal ·adj Having a habit of seeking food or moving about at night; as, nocturnal birds and insects.
III. Nocturnal ·adj Of, pertaining to, done or occuring in, the night; as, nocturnal darkness, cries, expedition, ·etc.;
— opposed to diurnal.