Eos (Ἠώς) is the Greek goddess of the dawn — the daughter of the Titan Hyperion, sister of Helios (the sun) and Selene (the moon). Each morning she rises from her bed in the eastern ocean to bring light to the world.
Eos as a girl's name is rare but rising as part of the broader return of classical Greek mythological names. The name conveys exactly its image: dawn, light, beginning.
Eos reduces to five — the number of dawning motion.