Where does “ча́ю” come from?

ча́ю (Russian) comes from Russian ча́ять, from Proto-Slavic čàjati — to expect, to wait.

Ancestry of “ча́ю”, step by step

StepLanguageWordMeaning
1Russianча́ятьto expect, to hope
2Proto-Slavicčàjatito expect, to wait

Words derived from “ча́ю

Every word from Proto-Slavic čàjatiEvery word from Russian ча́ять