The Collaborative International Dictionary of English v.0.48:

Wean \Wean\, v. t. [imp. & p. p. Weaned; p. pr. & vb. n.
   Weaning.] [OE. wenen, AS. wenian, wennan, to accustom; akin
   to D. wennen, G. gew["o]hnen, OHG. giwennan, Icel. venja, Sw.
   v[aum]nja, Dan. v[ae]nne, Icel. vanr accustomed, wont; cf.
   AS. [=a]wenian to wean, G. entw["o]hnen. See Wont, a.]
   [1913 Webster]
   1. To accustom and reconcile, as a child or other young
      animal, to a want or deprivation of mother's milk; to take
      from the breast or udder; to cause to cease to depend on
      the mother nourishment.
      [1913 Webster]

            And the child grew, and was weaned; and Abraham made
            a great feast the same day that Isaac was weaned.
                                                  --Gen. xxi. 8.
      [1913 Webster]

   2. Hence, to detach or alienate the affections of, from any
      object of desire; to reconcile to the want or loss of
      anything. "Wean them from themselves." --Shak.
      [1913 Webster]

            The troubles of age were intended . . . to wean us
            gradually from our fondness of life.  --Swift.
      [1913 Webster]

WordNet (r) 3.0 (2006):

weaning
    n 1: the act of substituting other food for the mother's milk in
         the diet of a child or young mammal [syn: weaning,
         ablactation]