Where does “key” come from?

key (Manx) comes from English quay, from Middle English keye, from Old French kay, from Gaulish kagyum, from Proto-Celtic kagyom, from Proto-Indo-European kagʰyóm, from Proto-Indo-European -yós — Creates adjectives from noun or verb stems.

key (Manx): cream; quay

Definitions

  1. cream; quay

Ancestry of “key”, step by step

key traces back through two separate lines of ancestry.

via English quay

StepLanguageWordMeaning
1EnglishquayA stone or concrete structure on navigable water...
2Middle EnglishkeyeA key; a tool for opening locks
3Old Frenchkay—
4Gaulishkagyum—
5Proto-Celtickagyompen, enclosure
6Proto-Indo-Europeankagʰyómenclosure, hedge
7Proto-Indo-European-yósCreates adjectives from noun or verb stems

via Manx kay

StepLanguageWordMeaning
1Manxkayfog
2PortuguesecéoSuperseded spelling of céu
3Proto-Celtic*kiwos—
4Proto-Indo-European(s)ḱih₃-wó-s—
5Proto-Indo-European(s)ḱeh₃-darkness, shadow
Every word from Proto-Indo-European -yós →Every word from Proto-Indo-European kagʰyóm →Every word from Proto-Celtic kagyom →