(Roman mythology) Of or pertaining to Neptune, the Roman god of fresh water and the sea, the counterpart of the Greek god Poseidon. / (by extension, rare) Of or pertaining to water or the sea.

(obsolete) A sailor. / (geology, historical) A proponent of Neptunism.

(astrology) Pertaining to the astrological influence of the planet Neptune. / (astronomy) Of or pertaining to the planet Neptune.

(astrology) A person under the astrological influence of the planet Neptune. / (chiefly science fiction) An (imaginary) inhabitant of the planet Neptune.

plural of Neptunian

Alternative letter-case form of Neptunian

Alternative letter-case form of Neptunian

plural of neptunian

lying beyond the orbit of the planet Neptune (especially with regard to planetary bodies)

(astronomy) Relating to an astronomical body found within the orbit of Neptune.