Old Norse otr

← Proto-Germanic *utraz (inherited)

← Proto-Indo-European *wed- (root)

← Proto-Indo-European *udrós (inherited)

→ Danish odder (inherited)

→ Faroese otur (derived)

→ Westrobothnian otter (inherited)

→ Icelandic otur (derived)

→ Latvian ūdrs (cognate)

→ Norwegian Bokmål oter (derived)

→ Norwegian Nynorsk oter (inherited)

→ Swedish utter (derived)