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]

WordNet (r) 3.0 (2006):

domesticate
    v 1: adapt (a wild plant or unclaimed land) to the environment;
         "domesticate oats"; "tame the soil" [syn: domesticate,
         cultivate, naturalize, naturalise, tame]
    2: overcome the wildness of; make docile and tractable; "He
       tames lions for the circus"; "reclaim falcons" [syn:
       domesticate, domesticize, domesticise, reclaim,
       tame]
    3: make fit for cultivation, domestic life, and service to
       humans; "The horse was domesticated a long time ago"; "The
       wolf was tamed and evolved into the house dog" [syn:
       domesticate, tame]

Moby Thesaurus II by Grady Ward, 1.0:

69 Moby Thesaurus words for "domesticate":
   acclimate, acclimatize, accommodate, accustom, adapt, adjust,
   anchor, billet at, bivouac, break, break in, break to harness,
   burrow, bust, camp, case harden, colonize, come to anchor,
   condition, confirm, domesticize, domiciliate, drop anchor,
   ensconce, establish, establish residence, familiarize, fix, gentle,
   habituate, harden, hive, housebreak, inhabit, inure, keep house,
   live at, locate, master, moor, move, naturalize, nest, orient,
   orientate, park, people, perch, populate, relocate, reside, roost,
   season, set up housekeeping, set up shop, settle, settle down,
   sit down, squat, stand, stay at, strike root, subdue,
   take residence at, take root, take up residence, tame, train,
   wont