Idunn or also Latin Iduna (Old Norse Iðunn "the renewer, the rejuvenator") is the goddess of youth and immortality in Norse mythology.
She is the youngest daughter of the older children of the dwarf Ivaldi and the wife of the divine singer Bragi, who won her over with a poem.
Idunn is the guardian of the golden apples, which give the gods eternal youth and thus immortality.
When Loki was captured by the giant Thiazi, the latter wanted to release him only if he handed over Idunn together with her golden apples.
When this happened, the gods immediately began to age and forced Loki to free the kidnapped girl from the giant's power.
Loki, dressed in Freya's falcon robe, transformed the captive into a nut and brought her back to Asgard, pursued by the giant in the form of an eagle, from which the fugitives escaped only by a hair's breadth. Thiazi was killed by the Aesir by burning his wings.
The goddess of the golden apples of immortality recalls the Greek myth of the golden apples of the tree of the Hesperides and may also have been borrowed from Greek mythology.
A borrowing from the Bible (the fruit from the tree of life in the Garden of Eden) is also conceivable.
The myth of the robbery of Idunn by a giant has some parallels with the relationship of the giants to Freya. A Celtic legend has been handed down from Ireland, in which three brothers in hawk's garb rob the miracle apples of Hisbernas.
They are pursued by the daughters of a king in the form of an eagle and barely escape. Also here a borrowing from the Hesperides seems to have taken place.
According to this, Idunn is not an original goddess of Norse mythology, but only a late addition.
According to another opinion, however, nothing proves that she did not belong to the Norse world of gods under another name.
Idun Peak in Antarctica and the asteroid (176) Iduna are named after her.