states' rights vs plural form

states' rights and plural form both are nouns.

Word	Noun	Adjective	Verb	Adverb
states' rights	Yes	No	No	No
plural form	Yes	No	No	No

states' rights (noun)	plural form (noun)
the rights conceded to the states by the United States constitution	the form of a word that is used to denote more than one
a doctrine that federal powers should be curtailed and returned to the individual states