Diner as in a place you go eat
Comedero (Eatery), Repostero, Cafetería [ka-fe-te-REE-ah]
(Coffee Shop)
Dinner as in a meal
Cena if it is an evening meal.
Almuerzo if it is an afternoon meal
(Parts of the US refer to Dinner as the afternoom meal and
Supper as the evening meal)