Pluto, in Greek mythology, the ruler of the underworld. His earlier name, Hades, was later applied to his domain. The Romans sometimes called him Pluto, but more often Tartarus, Dis, or Orcus. Pluto means “wealthy one" or “giver of riches," and Pluto often figured as a distributor of the wealth found beneath the earth. In this role, he was confused with Plutus, personification of wealth.