Proto-Germanic *lūkaną

→ English lock (inherited)

→ English louk (inherited)

→ English louk (inherited)

→ Old English lucan (inherited)

→ Danish nøgle (derived)

→ Danish lukke (derived)

→ Danish lykke (mention)

→ Middle Dutch luken (inherited)

→ French lucarne (mention)

→ Westrobothnian luuk (inherited)

→ Old Swedish luka (inherited)

→ Gothic 𐌲𐌰𐌻𐌿𐌺𐌰𐌽 (derived)

→ Gothic 𐌿𐍃𐌻𐌿𐌺𐌰𐌽 (derived)

→ Icelandic lok (inherited)

→ Icelandic ljúka (derived)

→ Dutch luiken (inherited)

→ Old Norse lúka (inherited)

→ Old Norse lykja (mention)

→ Old Frisian luka (inherited)

→ Old Saxon lukan (inherited)

→ Swedish nyckel (derived)

→ Swedish lycka (derived)

→ Swedish lucka (derived)