Where does “Cao” come from?

Cao (Czech) comes from Vietnamese cáo, from Chinese 告, from Middle Chinese 校.

Ancestry of “Cao”, step by step

StepLanguageWordMeaning
1Vietnamesecáoa fox; royal edict-like announcement
2Chinese告—
3Middle Chinese校—
Every word from Middle Chinese 校 →Every word from Chinese 告 →Every word from Vietnamese cáo →