black tie vs evening dress

black tie and evening dress both are nouns.

Word	Noun	Adjective	Verb	Adverb
black tie	Yes	No	No	No
evening dress	Yes	No	No	No

As nouns, evening dress is a hypernym of black tie; that is, evening dress is a word with a broader meaning than black tie:

Other hypernyms of black tie include evening clothes, eveningwear, formalwear.

black tie (noun)	evening dress (noun)
a black bow tie worn with a dinner jacket	attire to wear on formal occasions in the evening
semiformal evening dress for men