←
Proto-Germanic *arô (inherited)←
Proto-Germanic *dala- (inherited)←
Proto-Indo-European *h₃érō (inherited)←
Proto-Indo-European *dʰol- (inherited)←
Proto-Indo-European *dʰel- (mention)←
Old Norse arna (mention)←
Old Norse ǫrn (mention)←
Old Norse dalr (mention)