Don River vs Don

Don River and Don both are nouns.

Word	Noun	Adjective	Verb	Adverb
Don River	Yes	No	No	No
Don	Yes	No	No	No

As nouns, Don River and Don are synonyms defined as:

Don River and Don: a European river in southwestern Russia; flows into the Sea of Azov

Don River (noun)	Don (noun)
a European river in southwestern Russia; flows into the Sea of Azov	a Spanish courtesy title or form of address for men that is prefixed to the forename
	a European river in southwestern Russia; flows into the Sea of Azov
	Celtic goddess; mother of Gwydion and Arianrhod; corresponds to Irish Danu
	a Spanish gentleman or nobleman