In ancient Greek mythology and religion, Eos is the goddess and personification of the dawn, who rose each morning from her home at the edge of the river Oceanus to deliver light and disperse the night. In Greek tradition and poetry, she is characterized as a goddess with a great sexual appetite, who took numerous lovers for her own satisfaction and bore them several children. Like her Roman counterpart Aurora and Rigvedic Ushas, Eos continues the name of an earlier Indo-European dawn goddess, Hausos. Eos, or her earlier Proto-Indo-European (PIE) ancestor, also shares several elements with the love goddess Aphrodite, perhaps signifying Eos's influence on her or otherwise a common origin for the two goddesses. In surviving tradition, Aphrodite is the culprit behind Eos' numerous love affairs, having cursed the goddess with insatiable lust for mortal men.

Dawn is the time that marks the beginning of twilight before sunrise. It is recognized by the appearance of indirect sunlight being scattered in Earth's atmosphere, when the centre of the Sun's disc has reached 18° below the observer's horizon. This morning twilight period will last until sunrise, when direct sunlight outshines the diffused light.