Where does “sě” come from?

sě (Old Czech) comes from Proto-Slavic sę, from Proto-Balto-Slavic *sen, from Proto-Indo-European swé — self.

Ancestry of “sě”, step by step

StepLanguageWordMeaning
1Proto-Slavicsęoneself: myself, yourself, himself, herself,...
2Proto-Balto-Slavic*senoneself
3Proto-Indo-Europeanswéself

Words derived from “sě”

Every word from Proto-Indo-European swé →Every word from Proto-Balto-Slavic *sen →Every word from Proto-Slavic sę →
sě — Etymology, Origin & Word History | Etymology Explorer