river vs Yellowstone River

river and Yellowstone River both are nouns.

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

river (noun)	Yellowstone River (noun)
a large natural stream of water (larger than a creek)	a tributary of the Missouri River that flows through the Yellowstone National Park