Pertaining to night; as nocturnal darkness.

Done or happening at night; as a nocturnal expedition or assault; a nocturnal visit.

Nightly; done or being every night. From gilded roofs depending lamps display nocturnal beams, that emulate the day.

An instrument, chiefly used at sea to take the altitude of stars about the pole, in order to ascertain the latitude. This may be a hemisphere, or a planisphere on the plane of the equinoctial.