heathland vs Great Britain

heathland and Great Britain both are nouns.

Word	Noun	Adjective	Verb	Adverb
heathland	Yes	No	No	No
Great Britain	Yes	No	No	No

heathland (noun)	Great Britain (noun)
a tract of level wasteland; uncultivated land with sandy soil and scrubby vegetation	an island comprising England and Scotland and Wales
	a monarchy in northwestern Europe occupying most of the British Isles; divided into England and Scotland and Wales and Northern Ireland; `Great Britain' is often used loosely to refer to the United Kingdom