The city's modern name may derive from the Latin word meaning "knee" ("genu"; plural, "genua") but there are other theories. It could derive from the god Janus, because Genoa, like him, has two faces: a face that looks at the sea and another turned to the mountains. Or it could come from the Latin word "ianua", also related to the name of the God Janus, and meaning "door" or "passage." Besides that, it may refer to its geographical position at the centre of the Ligurian coastal arch, thus akin to the name of Geneva. The Latin name, "oppidum Genua", is recorded by Pliny the Elder ("Nat. Hist." 3.48) as part of the Augustean "Regio IX Liguria".