BalderPronunciation: /ˈbɔːldə/ Scandinavian MythologyDefinition of Balder a son of Odin and god of the summer sun. He was invulnerable to all things except mistletoe, with which the god Loki, by a trick, induced the blind god Hödur to kill him. Balder in other Oxford dictionaries Definition of Balder in the US English dictionary