Where does “бы́” come from?

бы́ (Russian) comes from Old East Slavic бꙑ, from Proto-Slavic *by.

Ancestry of “бы́”, step by step

StepLanguageWordMeaning
1Old East Slavicбꙑ—
2Proto-Slavic*by—

Words derived from “бы́”

Every word from Proto-Slavic *by →Every word from Old East Slavic бꙑ →