WordNet (r) 3.0 (2006):

mess hall
    n 1: a (large) military dining room where service personnel eat
         or relax [syn: mess, mess hall]

Moby Thesaurus II by Grady Ward, 1.0:

53 Moby Thesaurus words for "mess hall":
   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, messroom, pizzeria,
   quick-lunch counter, refectory, restaurant, salle a manger,
   smorgasbord, snack bar, tavern, tearoom, trattoria