Proto-Norse ᛊᚹᛖᛊᛏᚨᚱ

← Proto-Germanic *swestēr (inherited)

← Proto-Germanic (mention)

← Proto-Germanic *hwaþeraz (mention)

← Proto-Norse (mention)

← Proto-Indo-European *swésōr (inherited)

← Old Norse hvaðarr (mention)

→ Danish søster (inherited)

→ Faroese systir (derived)

→ Icelandic systir (derived)

→ Norwegian Bokmål søster (inherited)

→ Norwegian Nynorsk søster (inherited)

→ Norwegian Nynorsk syster (inherited)

→ Old Norse systir (inherited)

→ Swedish syster (inherited)