The Collaborative International Dictionary of English v.0.48:

Domesticate \Do*mes"ti*cate\, v. t. [imp. & p. p.
   Domesticated; p. pr. & vb. n. Domesticating.] [LL.
   domesticatus, p. p. of domesticare to reside in, to tame. See
   Domestic, a.]
   1. To make domestic; to habituate to home life; as, to
      domesticate one's self.
      [1913 Webster]

   2. To cause to be, as it were, of one's family or country;
      as, to domesticate a foreign custom or word.
      [1913 Webster]

   3. To tame or reclaim from a wild state; as, to domesticate
      wild animals; to domesticate a plant.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

domesticated \domesticated\ adj.
   1. tame, tamed; -- of animals. Opposite of wild.

   Syn: domestic.
        [WordNet 1.5 +PJC]

   2. accustomed to home life; as, some men think it unmanly to
      be domesticated; others find gratification in it.
      [WordNet 1.5]

   3. acclimated to a new environment; -- of plants or animals.

   Syn: naturalized, nonnative.
        [WordNet 1.5]

Moby Thesaurus II by Grady Ward, 1.0:

25 Moby Thesaurus words for "domesticated":
   broken, brought low, chastened, crushed, domestic, dovelike,
   gentle, housebroke, housebroken, humble, humbled, humiliated,
   lamblike, made to grovel, meek, mild, pacific, peaceable, quelled,
   quiet, reduced, subdued, submissive, tame, tamed