Rhein vs river

Rhein and river both are nouns.

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

Rhein (noun)	river (noun)
a major European river carrying more traffic than any other river in the world; flows into the North Sea	a large natural stream of water (larger than a creek)