The Collaborative International Dictionary of English v.0.48:

Gratis \Gra"tis\ (gr[a^]"t[i^]s or gr[=a]"t[i^]s), adv. [L.,
   contr. fr. gratiis out of favor or kindness, without
   recompense, for nothing, fr. gratia favor. See Grace.]
   For nothing; without fee or recompense; freely; gratuitously.
   [1913 Webster]

U.S. Gazetteer (1990):

Gratis, OH (village, FIPS 31472)
  Location: 39.64835 N, 84.52877 W
  Population (1990): 998 (348 housing units)
  Area: 2.4 sq km (land), 0.0 sq km (water)

Moby Thesaurus II by Grady Ward, 1.0:

29 Moby Thesaurus words for "gratis":
   as a gift, as our guest, charitable, complimentary, costless,
   eleemosynary, expenseless, for free, for love, for nothing,
   for the asking, free, free as air, free for nothing, free gratis,
   free of charge, free of cost, freebie, giftlike, given, gratuitous,
   gratuitously, on one, on the house, to his heirs, unbought,
   unpaid-for, untaxed, without charge