The Collaborative International Dictionary of English v.0.48:

Restaurant \Res"tau*rant\ (r?s"t?*r?nt;277), n. [F., fr.
   restaurer. See Restore.]
   An eating house.
   [1913 Webster]

WordNet (r) 3.0 (2006):

restaurant
    n 1: a building where people go to eat [syn: restaurant,
         eating house, eating place, eatery]

Moby Thesaurus II by Grady Ward, 1.0:

53 Moby Thesaurus words for "restaurant":
   automat, beanery, bistro, buffet, buvette, cafe, cafeteria,
   canteen, cantina, chophouse, chuck wagon, coffee shop, coffeehouse,
   coffeeroom, commons, cookhouse, cookshack, cookshop, diner,
   dinette, dining car, dining hall, dining room, dining saloon,
   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, lunchroom, mess, mess hall, messroom, pizzeria,
   quick-lunch counter, refectory, salle a manger, smorgasbord,
   snack bar, tavern, tearoom, trattoria