river vs Monongahela River

river and Monongahela River both are nouns.

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

river (noun)	Monongahela River (noun)
a large natural stream of water (larger than a creek)	a river that rises in northern West Virginia and flows north into Pennsylvania where it joins the Allegheny River at Pittsburgh to form the Ohio River