river vs Snake River

river and Snake River both are nouns.

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

river (noun)	Snake River (noun)
a large natural stream of water (larger than a creek)	a tributary of the Columbia River that rises in Wyoming and flows westward; discovered in 1805 by the Lewis and Clark Expedition