In Greek mythology, Eos (s/; Ionic and Homeric Greek Ἠώς Ēōs, Attic Ἕως Éōs, "dawn", pronounced [ɛːɔ̌ːs] or [héɔːs]; Aeolic Αὔως Aúōs, Doric Ἀώς Āṓs) is a Titaness and the goddess of the dawn, who rose each morning from her home at the edge of the Oceanus.
Eos had a brother and a sister, Helios, god of the sun, and Selene, goddess of the moon.
Eos is cognate to the Vedic goddess Ushas, Lithuanian goddess Aušrinė, and Roman goddess Aurora (Old Latin Ausosa), all three of whom are also goddesses of the dawn. All four are considered derivatives of the Proto-Indo-European stem *h₂ewsṓs (later *Ausṓs), "dawn", a stem that also gave rise to Proto-Germanic *Austrō, Old Germanic *Ōstara and Old English Ēostre / Ēastre. This agreement leads to the reconstruction of a Proto-Indo-European dawn goddess.