black tie vs dinner jacket

black tie and dinner jacket both are nouns.

Word	Noun	Adjective	Verb	Adverb
black tie	Yes	No	No	No
dinner jacket	Yes	No	No	No

As nouns, black tie and dinner jacket are synonyms defined as:

Other synonyms of black tie include tux, tuxedo.

black tie (noun)	dinner jacket (noun)
a black bow tie worn with a dinner jacket	semiformal evening dress for men
semiformal evening dress for men