Demerara River vs British Guiana

Demerara River and British Guiana both are nouns.

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

Demerara River (noun)	British Guiana (noun)
a river in northern Guyana that flows northward into the Atlantic	a republic in northeastern South America; formerly part of the British Empire, but it achieved independence from the United Kingdom in 1966