0 the planet eighth in order of distance and farthest from the Sun, after Uranus:
Neptune was discovered in 1846.
1 in Roman mythology (= ancient stories), the god of water and the sea:
The Romans identified Poseidon with their god of the sea, Neptune.
2 the planet eighth in order of distance from the sun, after Uranus and before Pluto
There was some old god called Neptune who could change himself into anything he liked.
The most striking of the museum's exhibits is a superb mosaic of Neptune surrounded by the four winds.
Figures of Neptune and a dolphin were intended to represent Russia's power at sea.
An artificial lake with a fountain sculpture of Neptune faces the house.
