Rare, chiefly historical: a navigational instrument for telling time at night by the stars.
Definitions
An instrument used to determine the time at night by observing the positions of certain stars. The sailor checked his nocturnal to make sure the ship stayed on course after sunset.
Foxes, bats, and other nocturnals emerge after dusk to feed.
Synonyms
night walker
night creature
nocturnal creature
night owl