Xinjiang Uighur Autonomous Region vs mainland China

Xinjiang Uighur Autonomous Region and mainland China both are nouns.

Word	Noun	Adjective	Verb	Adverb
Xinjiang Uighur Autonomous Region	Yes	No	No	No
mainland China	Yes	No	No	No

Xinjiang Uighur Autonomous Region (noun)	mainland China (noun)
an autonomous province in far northwestern China on the border with Mongolia and Kazakhstan; the largest province in the People's Republic of China and the homeland of the Uighur people	a communist nation that covers a vast territory in eastern Asia; the most populous country in the world