Where does “єсьмо” come from?

єсьмо (Ukrainian) comes from Proto-Slavic *esmъ.

Ancestry of “єсьмо”, step by step

StepLanguageWordMeaning
1Proto-Slavic*esmъ
Every word from Proto-Slavic *esmъ
єсьмо — Etymology, Origin & Word History | Etymology Explorer