Old Colony vs Mass.

Old Colony and Mass. both are nouns.

Word	Noun	Adjective	Verb	Adverb
Old Colony	Yes	No	No	No
Mass.	Yes	No	No	No

As nouns, Old Colony and Mass. are synonyms defined as:

Old Colony and Mass.: a state in New England, with capital Boston; one of the original 13 colonies

Other synonyms of Old Colony include Bay State, MA, Massachusetts.

Old Colony (noun)	Mass. (noun)
a state in New England, with capital Boston; one of the original 13 colonies	a state in New England, with capital Boston; one of the original 13 colonies