Orcus was a Roman god of the underworld.
Orcus may also refer to: Orcus (dwarf planet), a trans-Neptunian dwarf planet Orcus (beetle), a genus of beetles in the family Coccinellidae Orcus Patera, a large elongated depression the planet Mars Orcus (Dungeons & Dragons), a demon prince in the Dungeons & Dragons role-playing game Orcus, a major villain in the science fiction/fantasy Empire of the East series by Fred Saberhagen Orcus I, former designation of Dwarf planet Orcus' moon, Vanth