bellbottom trousers vs bell-bottoms

bellbottom trousers and bell-bottoms both are nouns.

Word	Noun	Adjective	Verb	Adverb
bellbottom trousers	Yes	No	No	No
bell-bottoms	Yes	No	No	No

As nouns, bellbottom trousers and bell-bottoms are synonyms defined as:

bellbottom trousers and bell-bottoms: (used in the plural) trousers with legs that flare; worn by sailors; absurdly wide hems were fashionable in the 1960s

Other synonyms of bellbottom trousers include bellbottom pants.

bellbottom trousers (noun)	bell-bottoms (noun)
(used in the plural) trousers with legs that flare; worn by sailors; absurdly wide hems were fashionable in the 1960s	(used in the plural) trousers with legs that flare; worn by sailors; absurdly wide hems were fashionable in the 1960s