French Republic vs the three estates

French Republic and the three estates both are nouns.

Word	Noun	Adjective	Verb	Adverb
French Republic	Yes	No	No	No
the three estates	Yes	No	No	No

French Republic (noun)	the three estates (noun)
a republic in western Europe; the largest country wholly in Europe	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