Where does “-а-” come from?

-а- (Moksha) comes from Old East Slavic -о-, from Proto-Slavic -o-.

Definitions

Ancestry of “-а-”, step by step

StepLanguageWordMeaning
1Old East Slavic-о-—
2Proto-Slavic-o-—

Words derived from “-а-”

Every word from Proto-Slavic -o- →Every word from Old East Slavic -о- →