From Old Norse Mjǫllnir, likely from Proto-Norse *ᛗᛖᛚᛞᚢᚾᛃᚨᛉ (*meldunjaʀ), from Proto-Germanic *meldunjaz, from Proto-Indo-European *meldʰ-n- (“lightning”).
From Old Norse Ásþrúðr, from Proto-Germanic *Ansuþrūþiz. Equivalent to ás (“(pagan) god; one of the æsir”) + þrúður (“strength”), cognate with Old English Ōsþrȳþ.
From Old Norse Mjǫllnir, likely from Proto-Norse *ᛗᛖᛚᛞᚢᚾᛃᚨᛉ (*meldunjaʀ), from Proto-Germanic *meldunjaz, from Proto-Indo-European *meldʰ-n- (“lightning”).