Old Norse þerna

← Proto-Germanic *þewernǭ (derived)

← Proto-Indo-European *tekʷ- (root)

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

← Old Norse þerna#Etymology_2_2 (mention)

← Old Saxon thiorna (borrowed)

→ English tern (derived)

→ Faroese terna (inherited)

→ Faroese terna (inherited)

→ French sterne (derived)

→ Icelandic þerna (inherited)

→ Icelandic þerna (inherited)

→ Norwegian Bokmål terne (derived)

→ Norwegian Nynorsk terne (derived)

→ Swedish tärna (derived)

→ Swedish tärna (derived)