DIn Norse mythology, a half-elf is the offspring of an elf and a human.

Notable examples include the Danish princess Skuld of Hrólf Kraki's saga, and the hero Högni of the Thidrekssaga (his mother was a human queen), and the royal line of Alfheim, which was related to the elves and more beautiful than other people, according to the Þorsteins saga Víkingssonar. (source)