bull session vs colloquialism

bull session and colloquialism both are nouns.

Word	Noun	Adjective	Verb	Adverb
bull session	Yes	No	No	No
colloquialism	Yes	No	No	No

bull session (noun)	colloquialism (noun)
an informal discussion (usually among men)	a colloquial expression; characteristic of spoken or written communication that seeks to imitate informal speech