People's Republic of China vs Cathay

People's Republic of China and Cathay both are nouns.

Word	Noun	Adjective	Verb	Adverb
People's Republic of China	Yes	No	No	No
Cathay	Yes	No	No	No

As nouns, People's Republic of China and Cathay are synonyms defined as:

People's Republic of China and Cathay: a communist nation that covers a vast territory in eastern Asia; the most populous country in the world

Other synonyms of People's Republic of China include China, Communist China, mainland China, PRC, Red China.

People's Republic of China (noun)	Cathay (noun)
a communist nation that covers a vast territory in eastern Asia; the most populous country in the world	a communist nation that covers a vast territory in eastern Asia; the most populous country in the world