The Collaborative International Dictionary of English v.0.48:

Judge \Judge\ (j[u^]j), n. [OE. juge, OF. & F. juge, fr. OF.
   jugier, F. juger, to judge. See Judge, v. i.]
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   1. (Law) A public officer who is invested with authority to
      hear and determine litigated causes, and to administer
      justice between parties in courts held for that purpose.
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            The parts of a judge in hearing are four: to direct
            the evidence; to moderate length, repetition, or
            impertinency of speech; to recapitulate, select, and
            collate the material points of that which hath been
            said; and to give the rule or sentence. --Bacon.
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   2. One who has skill, knowledge, or experience, sufficient to
      decide on the merits of a question, or on the quality or
      value of anything; one who discerns properties or
      relations with skill and readiness; a connoisseur; an
      expert; a critic.
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            A man who is no judge of law may be a good judge of
            poetry, or eloquence, or of the merits of a
            painting.                             --Dryden.
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   3. A person appointed to decide in a trial of skill, speed,
      etc., between two or more parties; an umpire; as, a judge
      in a horse race.
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   4. (Jewish Hist.) One of the supreme magistrates, with both
      civil and military powers, who governed Israel for more
      than four hundred years.
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   5. pl. The title of the seventh book of the Old Testament;
      the Book of Judges.
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   Judge Advocate (Mil. & Nav.), a person appointed to act as
      prosecutor at a court-martial; he acts as the
      representative of the government, as the responsible
      adviser of the court, and also, to a certain extent, as
      counsel for the accused, when he has no other counsel.

   Judge-Advocate General, in the United States, the title of
      two officers, one attached to the War Department and
      having the rank of brigadier general, the other attached
      to the Navy Department and having the rank of colonel of
      marines or captain in the navy. The first is chief of the
      Bureau of Military Justice of the army, the other performs
      a similar duty for the navy. In England, the designation
      of a member of the ministry who is the legal adviser of
      the secretary of state for war, and supreme judge of the
      proceedings of courts-martial.

   Syn: Judge, Umpire, Arbitrator, Referee.

   Usage: A judge, in the legal sense, is a magistrate appointed
          to determine questions of law. An umpire is a person
          selected to decide between two or more who contend for
          a prize. An arbitrator is one chosen to allot to two
          contestants their portion of a claim, usually on
          grounds of equity and common sense. A referee is one
          to whom a case is referred for final adjustment.
          Arbitrations and references are sometimes voluntary,
          sometimes appointed by a court.
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The Collaborative International Dictionary of English v.0.48:

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.
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   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.
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   2. One who defends, vindicates, or espouses any cause by
      argument; a pleader; as, an advocate of free trade, an
      advocate of truth.
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   3. Christ, considered as an intercessor.
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            We have an Advocate with the Father.  --1 John ii.
                                                  1.
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   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.
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WordNet (r) 3.0 (2006):

judge advocate
    n 1: an officer assigned to the judge advocate general
    2: a staff officer serving as legal adviser to a military
       commander

Bouvier's Law Dictionary, Revised 6th Ed (1856):

JUDGE ADVOCATE. An officer who, is a member of a court martial.
     2. His duties are to prosecute in the name of the United States, but he
shall so far consider himself as counsel for the prisoner, after the
prisoner shall have made his plea, as to object to leading questions to any
of the witnesses, or any question to the prisoner, the answer to which might
tend to criminate himself. He is further to swear the members of the court
before they proceed upon any trial. Rules and Articles of War, art. 69, 2
Story, L. U. S. 1001; Lid. Jud. Adv. passim.