river vs Demerara River

river and Demerara River both are nouns.

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

river (noun)	Demerara River (noun)
a large natural stream of water (larger than a creek)	a river in northern Guyana that flows northward into the Atlantic