Where does “kei” come from?

kei (Translingual) comes from English Kei, from Japanese 系, from Middle Chinese 系.

Ancestry of “kei”, step by step

StepLanguageWordMeaning
1EnglishKeiA class of lightweight vehicles with small engines
2Japanese系system, family
3Middle Chinese系—
Every word from Middle Chinese 系 →Every word from Japanese 系 →Every word from English Kei →