Nomenclature
The Russian hydronym Volga (Волга) derives from Proto-Slavic *vòlga "wetness, moisture", which is preserved in many Slavic languages, including Ukrainian vológa (воло́га) "moisture", Russian vlaga (влага) "moisture", Bulgarian vlaga (влага) "moisture", Czech vláha "dampness", and Serbo-Croatian vlȁga "moisture", among others.
The Slavic name is a loan translation of earlier Scythian Rā (Ῥᾶ) "Volga", literally "wetness", seen also in Avestan Raŋhā "mythical stream" and Sogdian r’k "vein, blood vessel" (< *raha-ka), and cognate with Sanskrit rasā́h "liquid, juice; mythical river". The Scythian name survives in modern Mordvin Rav (Рав) "Volga".
The Turkic peoples living along the river formerly referred to it as Itil or Atil "big river". In modern Turkic languages, the Volga is known as İdel (Идел) in Tatar, Атăл (Atăl) in Chuvash, Idhel in Bashkir, Edil in Kazakh, and İdil in Turkish. The Turkic peoples associated the Itil's origin with the Kama River. Thus, a left tributary to the Kama River was named the Aq Itil "White Itil" which unites with the Kara Itil "Black Itil" at the modern city of Ufa.The name Indyl (Indɨl) is used in Adyge (Cherkess) language.
Among Asians the river was known by its other Turkic name Sarı-su "yellow water", but Mongols also used their own name: Ijil mörön "adaptation river". Presently the Mari, another Ugric group, call the river Юл (Jul), meaning "way" in Tatar. Formerly, they called the river Volgydo, a borrowing from Old Russian.
Read more about this topic: Volga River