river vs North Platte River

river and North Platte River both are nouns.

Word	Noun	Adjective	Verb	Adverb
river	Yes	No	No	No
North Platte River	Yes	No	No	No

river (noun)	North Platte River (noun)
a large natural stream of water (larger than a creek)	a river that rises in northern Colorado and flows northward into Wyoming and then eastward and southeastward through Nebraska where it joins the South Platte to form the Platte River