white tie vs evening dress

white tie and evening dress both are nouns.

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

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

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

white tie (noun)	evening dress (noun)
bow tie worn as part of a man's formal evening dress	attire to wear on formal occasions in the evening
formalwear consisting of full evening dress for men