Hades three-headed guard dog Cerberus. The Etruscan god Aita and the Roman gods Dis Pater and Orcus were eventually taken as equivalent to Hades and merged into Pluto, a Latinization of Plouton (", Ploútōn"), itself a euphemistic title often given to Hades. The origin of Hades' name is uncertain, but has generally been seen as meaning "the unseen one" since antiquity. An extensive section of Plato's dialogue "Cratylus" is devoted to the etymology of the god's name, in which Socrates is arguing for a folk etymology not from "unseen" but from "his knowledge ("eidenai") of all noble things". Modern linguists have
Gate deities of the underworld only to the souls capable of pronouncing the secret name of the god himself, as a sort of "password". The walls of many Pharaonic tombs in the Valley of the Kings are decorated with the texts of the Book of Gates, which describes the twelve gates or pylons of the underworld: in spite of being imagined as architectural barriers to all intents and purposes, the gates were individually named as goddesses. Chapter 144 of the Book of the Dead mentions seven gates, each with its own God, a Doorkeeper and a Herald: for example, the 7th gate is guarded by