Rappahannock River vs river

Rappahannock River and river both are nouns.

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

Rappahannock River (noun)	river (noun)
a river that flows across eastern Virginia into the Tidewater region	a large natural stream of water (larger than a creek)