Source : Webster's Revised Unabridged Dictionary (1913)

Transubstantiate \Tran`sub*stan"ti*ate\, v. t. [LL.
   transubstantiatus, p. p. of transubstantiare to
   transubstantiate; L. trans across, over + substantia
   substance. See {Substance}.]
   1. To change into another substance. [R.]

            The spider love which transubstantiates all, And can
            convert manna to gall.                --Donne.

   2. (R. C. Theol.) To change, as the sacramental elements,
      bread and wine, into the flesh and blood of Christ.

Source : WordNet®

transubstantiate
     v 1: change (the Eucharist bread and wine) into the body and
          blood of Christ
     2: change or alter in form, appearance, or nature; "This
        experience transformed her completely"; "She transformed
        the clay into a beautiful sculpture"; "transubstantiate
        one element into another" [syn: {transform}, {transmute}]