Neckar River vs river

Neckar River and river both are nouns.

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

Neckar River (noun)	river (noun)
a river in Germany; rises in the Black Forest and flows north into the Rhine	a large natural stream of water (larger than a creek)