Naming of moons underworld, and Nix (a respelling of Nyx), mother of Charon, is the goddess of darkness and the night. Kerberos is a giant three-headed dog who guards the entrance to the underworld. The fifth moon is named for the river Styx that forms the boundary between the worlds of the living and the dead. The name of Eris's moon Dysnomia was suggested by its discoverer Michael E. Brown, who also suggested the name of the dwarf planet. The name has two meanings: in mythology Dysnomia (lawlessness) is the daughter of Eris (chaos). However, the name is also an intentional reference to
Pluto (mythology) the underworld. "Plūtō" (; genitive "Plūtōnis") is the Latinized form of the Greek "Plouton". Pluto's Roman equivalent is Dis Pater, whose name is most often taken to mean "Rich Father" and is perhaps a direct translation of "Plouton." Pluto was also identified with the obscure Roman Orcus, like Hades the name of both a god of the underworld and the underworld as a place. The borrowed Greek name "Pluto" is sometimes used for the ruler of the dead in Latin literature, leading some mythology handbooks to assert misleadingly that Pluto was the Roman counterpart of Hades. "Pluto" ("Pluton" in French