Arno River vs river

Arno River and river both are nouns.

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

Arno River (noun)	river (noun)
a river in central Italy rising in the Apennines and flowing through Florence and Pisa to the Ligurian Sea	a large natural stream of water (larger than a creek)