Source : Webster's Revised Unabridged Dictionary (1913)

Surrogate \Sur"ro*gate\, n. [L. surrogatus, p. p. of surrogare,
   subrogare, to put in another's place, to substitute; sub
   under + rogare to ask, ask for a vote, propose a law. See
   {Rogation}, and cf. {Subrogate}.]
   1. A deputy; a delegate; a substitute.

   2. The deputy of an ecclesiastical judge, most commonly of a
      bishop or his chancellor, especially a deputy who grants
      marriage licenses. [Eng.]

   3. In some States of the United States, an officer who
      presides over the probate of wills and testaments and
      yield the settlement of estates.

Surrogate \Sur"ro*gate\, v. t.
   To put in the place of another; to substitute. [R.] --Dr. H.
   More.

Source : WordNet®

surrogate
     adj : providing or receiving nurture or parental care though not
           related by blood or legal ties; "foster parent";
           "foster child"; "foster home"; "surrogate father" [syn:
            {foster}]

surrogate
     n 1: someone who takes the place of another person [syn: {alternate},
           {replacement}]
     2: a person appointed to represent or act on behalf of others
        [syn: {deputy}]