Old Norse fiðri

← Proto-Germanic *fiþriją (inherited)

← Proto-Germanic *feþrō (mention)

← Proto-Indo-European *peth₂- (root)

← Proto-Indo-European *peth₂- (derived)

→ Westrobothnian førel (mention)

→ Icelandic fiðrildi (mention)

→ Icelandic fiður (inherited)

→ Old Norse fiðraðr (suffix)

→ Swedish fjäril (mention)