Volga vs river

Volga and river both are nouns.

Word	Noun	Adjective	Verb	Adverb
Volga	Yes	No	No	No
river	Yes	No	No	No

Volga (noun)	river (noun)
a Russian river; the longest river in Europe; flows into the Caspian Sea	a large natural stream of water (larger than a creek)