Neptune

Neptune in Roman religion and mythology, god of water. He was presumably an indigenous god of fertility, but in later times he was identified with the Greek Poseidon , god of the sea. At his festival, the Neptunalia (July 23), arbors were dedicated to him.

Neptune in Roman mythology, the god of the water and of the sea; his Greek equivalent is Poseidon.

From the early 19th century, the traditional shipboard ceremony held when crossing the equator has included a sailor dressed as Neptune.
Neptunism was a theory propounded by A. G. Werner that the rocks of the earth's crust were formed primarily by crystallization from the sea, rather than by solidification of magma. The theory was popular at the end of the 18th and the beginning of the 19th century, but is now rejected.

Neptune Roman god, originally associated with freshwater but later identified with the Greek god Poseidon and hence the sea. He was often depicted carrying a trident and riding a dolphin. His festival was in July.