river vs Indigirka River

river and Indigirka River both are nouns.

Word	Noun	Adjective	Verb	Adverb
river	Yes	No	No	No
Indigirka River	Yes	No	No	No

river (noun)	Indigirka River (noun)
a large natural stream of water (larger than a creek)	a river in far eastern Siberia that flows generally northward to the Arctic Ocean