Demerara River vs Demerara

Demerara River and Demerara both are nouns.

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

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

Demerara River and Demerara: a river in northern Guyana that flows northward into the Atlantic

Demerara River (noun)	Demerara (noun)
a river in northern Guyana that flows northward into the Atlantic	a former Dutch colony in South America; now a part of Guyana
	a river in northern Guyana that flows northward into the Atlantic