Kuenlun Mountains vs mainland China

Kuenlun Mountains and mainland China both are nouns.

Word	Noun	Adjective	Verb	Adverb
Kuenlun Mountains	Yes	No	No	No
mainland China	Yes	No	No	No

Kuenlun Mountains (noun)	mainland China (noun)
a mountain range in western China that extends eastward from the Indian border for 1000 miles	a communist nation that covers a vast territory in eastern Asia; the most populous country in the world