adjective: (Roman mythology) Of or pertaining to Neptune, the Roman god of fresh water and the sea, the counterpart of the Greek god Poseidon.
adjective: (by extension, rare) Of or pertaining to water or the sea.
adjective: (by extension, geology) Formed by the action of water.
adjective: (by extension, geology, historical) Of, pertaining to, or supporting Neptunism (“a discredited theory that rocks were formed from the crystallisation of minerals in the early Earth's oceans”).
noun: (obsolete) A sailor.
noun: (geology, historical) A proponent of Neptunism.
adjective: (astrology) Pertaining to the astrological influence of the planet Neptune.
adjective: (astronomy) Of or pertaining to the planet Neptune.
noun: (astrology) A person under the astrological influence of the planet Neptune.
noun: (chiefly science fiction) An (imaginary) inhabitant of the planet Neptune.
adjective: Alternative letter-case form of Neptunian [(Roman mythology) Of or pertaining to Neptune, the Roman god of fresh water and the sea, the counterpart of the Greek god Poseidon.]
noun: Alternative letter-case form of Neptunian [(obsolete) A sailor.]