Rhein vs Rhine River

Rhein and Rhine River both are nouns.

Word	Noun	Adjective	Verb	Adverb
Rhein	Yes	No	No	No
Rhine River	Yes	No	No	No

As nouns, Rhein and Rhine River are synonyms defined as:

Rhein and Rhine River: a major European river carrying more traffic than any other river in the world; flows into the North Sea

Other synonyms of Rhein include Rhine.

Rhein (noun)	Rhine River (noun)
a major European river carrying more traffic than any other river in the world; flows into the North Sea	a major European river carrying more traffic than any other river in the world; flows into the North Sea