Lunchroom

Noun

 * 1) A room reserved for eating food, especially at a business (lunch may or may not be served there).
 * We made a point to eat in the lunchroom not at our desks.
 * 1) A diner or restaurant that specializes in serving lunch.
 * I don't know how they stay in business serving only lunch, but the lunchroom on the corner is cheap and fast so I like it.

Thesaurus
automat, beanery, bistro, buffet, buvette, cafe, cafeteria, canteen, cantina, chophouse, chuck wagon, coffee, coffee shop, coffeehouse, coffeeroom, cookhouse, cookshack, cookshop, diner, dining hall, dining room, dog wagon, drive-in, drive-in restaurant, eatery, eating house, fast-food chain, grill, grillroom, hamburger stand, hash house, hashery, hot-dog stand, kitchen, lunch counter, lunch wagon, luncheonette, mess hall, pizzeria, quick-lunch counter, restaurant, smorgasbord, snack bar, tavern, tearoom, trattoria

Synonyms

 * cafeteria