Noun
(Roman mythology) god of the underworld; counterpart of Greek Hades
Source: WordNetIndeed, the genus name Orcinus means "of the kingdom of the dead",sfn or "belonging to Orcus ". Source: Internet
However, the two are constrained by their mutual resonance with Neptune to always be in opposite phases of their orbits; Orcus is thus sometimes described as the "anti-Pluto". Source: Internet