1. A person eating a meal (especially in a restaurant)
   "The diner complained about the slow service"
    
2. A restaurant that resembles a dining car
   "They stopped at a roadside diner for breakfast"
    
3. A passenger car where food is served in transit
   "We enjoyed dinner in the diner as the train sped through the countryside";
   - dining car, dining compartment, buffet car

Derived forms: diners

Type of: carriage, coach, eater, eatery [informal], eating house, eating place, feeder, passenger car, restaurant, resto [N. Amer, informal]

Encyclopedia: Diner