river vs Orinoco River

river and Orinoco River both are nouns.

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

river (noun)	Orinoco River (noun)
a large natural stream of water (larger than a creek)	a South American river 1,500 miles long; flows into the South Atlantic