river vs Nizhnyaya Tunguska River

river and Nizhnyaya Tunguska River both are nouns.

Word	Noun	Adjective	Verb	Adverb
river	Yes	No	No	No
Nizhnyaya Tunguska River	Yes	No	No	No

river (noun)	Nizhnyaya Tunguska River (noun)
a large natural stream of water (larger than a creek)	a river that arises to the north of Lake Baikal and flows north and west to the Yenisei River