How Were the Planets Named?
All of the planets, except for Earth, were named after Greek and Roman gods and goddesses. There were five planets that were visible to ancient Greek and Roman astronomers.
They named these planets after their gods: Jupiter – the king of the gods, Venus – the goddess of love and beauty. Mars – the god of war, Mercury – the swift messenger of the gods, and Saturn – the god of harvest.
The planets that have been discovered since Roman times have been named for other Greek and Roman gods. Uranus was named for the Roman god of the heavens, Neptune for the Roman god of the sea, and Pluto for the god who ruled the underworld of myth, who was able to render himself invisible.
The name Earth is an English/German name which simply means the ground.