Source : Webster's Revised Unabridged Dictionary (1913)

Advocate \Ad"vo*cate\, n. [OE. avocat, avocet, OF. avocat, fr.
   L. advocatus, one summoned or called to another; properly the
   p. p. of advocare to call to, call to one's aid; ad + vocare
   to call. See {Advowee}, {Avowee}, {Vocal}.]
   1. One who pleads the cause of another. Specifically: One who
      pleads the cause of another before a tribunal or judicial
      court; a counselor.

   Note: In the English and American Law, advocate is the same
         as ``counsel,'' ``counselor,'' or ``barrister.'' In the
         civil and ecclesiastical courts, the term signifies the
         same as ``counsel'' at the common law.

   2. One who defends, vindicates, or espouses any cause by
      argument; a pleader; as, an advocate of free trade, an
      advocate of truth.

   3. Christ, considered as an intercessor.

            We have an Advocate with the Father.  --1 John ii.
                                                  1.

   {Faculty of advocates} (Scot.), the Scottish bar in
      Edinburgh.

   {Lord advocate} (Scot.), the public prosecutor of crimes, and
      principal crown lawyer.

   {Judge advocate}. See under {Judge}.

Advocate \Ad"vo*cate\, v. i.
   To act as advocate. [Obs.] --Fuller.

Advocate \Ad"vo*cate\, v. t. [imp. & p. p. {Advocated}; p. pr. &
   vb. n. {Advocating}.] [See {Advocate}, n., {Advoke}, {Avow}.]
   To plead in favor of; to defend by argument, before a
   tribunal or the public; to support, vindicate, or recommend
   publicly.

         To advocate the cause of thy client.     --Bp.
                                                  Sanderson
                                                  (1624).

         This is the only thing distinct and sensible, that has
         been advocated.                          --Burke.

         Eminent orators were engaged to advocate his cause.
                                                  --Mitford.

Source : WordNet®

advocate
     n 1: a person who pleads for a cause or propounds an idea [syn: {advocator},
           {proponent}, {exponent}]
     2: a lawyer who pleads cases in court [syn: {counsel}, {counselor},
         {counsellor}, {counselor-at-law}, {pleader}]
     v 1: push for something; "The travel agent recommended strongly
          that we not travel on Thanksgiving Day" [syn: {recommend},
           {urge}]
     2: speak, plead, or argue in favour of; "The doctor advocated a
        smoking ban in the entire house" [syn: {preach}]