bellbottom trousers vs plural

bellbottom trousers and plural both are nouns.

Word	Noun	Adjective	Verb	Adverb
bellbottom trousers	Yes	No	No	No
plural	Yes	Yes	No	No

bellbottom trousers (noun)	plural (noun)
(used in the plural) trousers with legs that flare; worn by sailors; absurdly wide hems were fashionable in the 1960s	the form of a word that is used to denote more than one

bellbottom trousers (adjective)	plural (adjective)
	grammatical number category referring to two or more items or units
	composed of more than one member, set, or kind