dinner jacket vs eveningwear

dinner jacket and eveningwear both are nouns.

Word	Noun	Adjective	Verb	Adverb
dinner jacket	Yes	No	No	No
eveningwear	Yes	No	No	No

As nouns, eveningwear is a hypernym of dinner jacket; that is, eveningwear is a word with a broader meaning than dinner jacket:

Other hypernyms of dinner jacket include evening clothes, evening dress, formalwear.

dinner jacket (noun)	eveningwear (noun)
semiformal evening dress for men	attire to wear on formal occasions in the evening