Maritime Provinces vs Maritimes

Maritime Provinces and Maritimes both are nouns.

Word	Noun	Adjective	Verb	Adverb
Maritime Provinces	Yes	No	No	No
Maritimes	Yes	No	No	No

As nouns, Maritime Provinces and Maritimes are synonyms defined as:

Maritime Provinces and Maritimes: the collective name for the Canadian provinces of New Brunswick and Nova Scotia and Prince Edward Island

Other synonyms of Maritime Provinces include Canadian Maritime Provinces, The Maritimes.

Maritime Provinces (noun)	Maritimes (noun)
the collective name for the Canadian provinces of New Brunswick and Nova Scotia and Prince Edward Island	the collective name for the Canadian provinces of New Brunswick and Nova Scotia and Prince Edward Island