river vs Rappahannock

river and Rappahannock both are nouns.

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

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