river vs Amazon River

river and Amazon River both are nouns.

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

river (noun)	Amazon River (noun)
a large natural stream of water (larger than a creek)	a major South American river; arises in the Andes and flows eastward into the South Atlantic; the world's 2nd longest river (4000 miles)