Where does “марьня” come from?

марьня (Moksha) comes from Moksha марь, from Proto-Mordvinic *maŕ, from Proto-Uralic *mërja — berry.

Ancestry of “марьня”, step by step

StepLanguageWordMeaning
1Mokshaмарьapple
2Proto-Mordvinic*maŕberry
3Proto-Uralic*mërjaberry
Every word from Proto-Uralic *mërja →Every word from Proto-Mordvinic *maŕ →Every word from Moksha марь →