Keystone State vs Pennsylvania

Keystone State and Pennsylvania both are nouns.

Word	Noun	Adjective	Verb	Adverb
Keystone State	Yes	No	No	No
Pennsylvania	Yes	No	No	No

As nouns, Keystone State and Pennsylvania are synonyms defined as:

Keystone State and Pennsylvania: a Mid-Atlantic state; one of the original 13 colonies, with capital Harrisburg

Other synonyms of Keystone State include Pa., PA.

Keystone State (noun)	Pennsylvania (noun)
a Mid-Atlantic state; one of the original 13 colonies, with capital Harrisburg	a university in Philadelphia, Pennsylvania
	a Mid-Atlantic state; one of the original 13 colonies, with capital Harrisburg
	one of the British colonies that formed the United States, with capital Philadelphia