Ruhr vs river

Ruhr and river both are nouns.

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

Ruhr (noun)	river (noun)
a major industrial and coal mining region in the valley of the Ruhr river in northwestern Germany	a large natural stream of water (larger than a creek)
a tributary of the Rhine