Where does “Беларусь” come from?

Беларусь (Mongolian) comes from Russian Белару́сь, from Belarusian Белару́сь, from Old East Slavic Бѣла Русь — {{w|White Ruthenia}} or White Rus.

Ancestry of “Беларусь”, step by step

StepLanguageWordMeaning
1RussianБелару́сьsee usage notes
2BelarusianБелару́сь—
3Old East SlavicБѣла Русь{{w|White Ruthenia}} or White Rus
Every word from Old East Slavic Бѣла Русь →Every word from Belarusian Белару́сь →Every word from Russian Белару́сь →