diner vs restaurant

diner and restaurant both are nouns.

Word	Noun	Adjective	Verb	Adverb
diner	Yes	No	No	No
restaurant	Yes	No	No	No

As nouns, restaurant is a hypernym of diner; that is, restaurant is a word with a broader meaning than diner:

Other hypernyms of diner include eatery, eating house, eating place.

diner (noun)	restaurant (noun)
a passenger car where food is served in transit	a building where people go to eat
a restaurant that resembles a dining car
a person eating a meal (especially in a restaurant)