Iðunn (Old Norse: Iðunn) is a goddess associated with youth and rejuvenation, principally through her role as the keeper of the apples that maintain the gods’ eternal youth. Her abduction and recovery constitute the primary mythological episode in which she appears, preserved in two main sources: the skaldic poem Haustlöng by Þjóðólfr of Hvinir (late ninth century) and the Prose Edda’s Skáldskaparmál. Iðunn is lured outside Ásgarðr by Loki — under compulsion from the giant Þjazi — on the pretense of better apples found nearby. Þjazi, in eagle form, seizes her and takes her to his mountain home Þrymheimr. Without her apples, the gods begin to age rapidly.

Loki is sent to retrieve Iðunn: he transforms into a falcon using Freyja’s feather-cloak, transforms Iðunn into a nut, and flies her back to Ásgarðr. Þjazi pursues in eagle form but is killed by fire lit by the Æsir at Ásgarðr’s walls.

Iðunn is described in Gylfaginning as the wife of Bragi and the keeper of the apples which the gods must taste when they begin to age. A reference in Lokasenna (st. 17) accuses Iðunn of having embraced the killer of her brother, whose context is unclear and may reference a myth otherwise lost.