River Ouse vs river

River Ouse and river both are nouns.

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

River Ouse (noun)	river (noun)
a river in northeastern England that flows generally southeastward to join the Trent River and form the Humber	a large natural stream of water (larger than a creek)