Where does “истъ” come from?

истъ (Old Church Slavonic) comes from Proto-Slavic jistъ — true, genuine; same.

истъ (Old Church Slavonic): true

Definitions

  1. true

Ancestry of “истъ”, step by step

StepLanguageWordMeaning
1Proto-Slavicjistъtrue, genuine; same
Every word from Proto-Slavic jistъ