Icelandic fer-

← Proto-Germanic *feþur- (inherited)

← Proto-Indo-European *kʷetwr̥- (inherited)

← Proto-Indo-European *kʷetwóres (mention)

← Old Norse fer- (inherited)

→ Icelandic fern (mention)

→ Icelandic ferstrendingur (affix)

→ Icelandic fermetri (affix)

→ Icelandic ferkílómetri (affix)

→ Icelandic fermíla (affix)