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]

WordNet (r) 3.0 (2006):

gratis
    adv 1: without payment; "I'll give you this gratis" [syn:
           gratis, for free, free of charge]
    adj 1: costing nothing; "complimentary tickets"; "free
           admission" [syn: complimentary, costless, free,
           gratis(p), gratuitous]

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



U.S. Gazetteer Places (2000):

Gratis, OH -- U.S. village in Ohio
   Population (2000):    934
   Housing Units (2000): 361
   Land area (2000):     0.944171 sq. miles (2.445391 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    0.944171 sq. miles (2.445391 sq. km)
   FIPS code:            31472
   Located within:       Ohio (OH), FIPS 39
   Location:             39.649326 N, 84.527551 W
   ZIP Codes (1990):
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Gratis, OH
    Gratis