Commons vs the three estates

Commons and the three estates both are nouns.

Word	Noun	Adjective	Verb	Adverb
Commons	Yes	No	No	No
the three estates	Yes	No	No	No

As nouns, the three estates is a hypernym of Commons; that is, the three estates is a word with a broader meaning than Commons:

Commons: the common people
the three estates: a major social class or order of persons regarded collectively as part of the body politic of the country (especially in the United Kingdom) and formerly possessing distinct political rights

Other hypernyms of Commons include estate, estate of the realm.

Commons (noun)	the three estates (noun)
the common people	a major social class or order of persons regarded collectively as part of the body politic of the country (especially in the United Kingdom) and formerly possessing distinct political rights