In ancient Roman religion and myth, Faunus was the rustic god of the forest, plains and fields; when he made cattle fertile, he was called Inuus. He came to be equated in literature with the Greek god Pan, after which Romans depicted him as a horned god.

In ancient Roman religion, Inuus was a god, or aspect of a god, who embodied sexual intercourse. The evidence for him as a distinct entity is scant. Maurus Servius Honoratus wrote that Inuus is an epithet of Faunus, named from his habit of intercourse with animals, based on the etymology of ineundum, "a going in, penetration," from inire, "to enter" in the sexual sense. Other names for the god were Fatuus and Fatuclus.