The Collaborative International Dictionary of English v.0.48:

Attorney \At*tor"ney\, n.; pl. Attorneys. [OE. aturneye, OF.
   atorn['e], p. p. of atorner: cf. LL. atturnatus, attornatus,
   fr. attornare. See Attorn.]
   1. A substitute; a proxy; an agent. [Obs.]
      [1913 Webster]

            And will have no attorney but myself. --Shak.
      [1913 Webster]

   2. (Law)
      (a) One who is legally appointed by another to transact
          any business for him; an attorney in fact.
      (b) A legal agent qualified to act for suitors and
          defendants in legal proceedings; an attorney at law.
          [1913 Webster]

   Note: An attorney is either public or private. A private
         attorney, or an attorney in fact, is a person appointed
         by another, by a letter or power of attorney, to
         transact any business for him out of court; but in a
         more extended sense, this class includes any agent
         employed in any business, or to do any act in pais, for
         another. A public attorney, or attorney at law, is a
         practitioner in a court of law, legally qualified to
         prosecute and defend actions in such court, on the
         retainer of clients. --Bouvier. -- The attorney at law
         answers to the procurator of the civilians, to the
         solicitor in chancery, and to the proctor in the
         ecclesiastical and admiralty courts, and all of these
         are comprehended under the more general term lawyer. In
         Great Britain and in some states of the United States,
         attorneys are distinguished from counselors in that the
         business of the former is to carry on the practical and
         formal parts of the suit. In many states of the United
         States however, no such distinction exists. In England,
         since 1873, attorneys at law are by statute called
         solicitors.
         [1913 Webster]

   A power, letter, or warrant, of attorney, a written
      authority from one person empowering another to transact
      business for him.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Attorney \At*tor"ney\, v. t.
   To perform by proxy; to employ as a proxy. [Obs.] --Shak.
   [1913 Webster]

WordNet (r) 3.0 (2006):

attorney
    n 1: a professional person authorized to practice law; conducts
         lawsuits or gives legal advice [syn: lawyer, attorney]

Moby Thesaurus II by Grady Ward, 1.0:

70 Moby Thesaurus words for "attorney":
   MC, advocate, agent, alter ego, alternate, amicus curiae, assignee,
   attorney-at-law, backup, backup man, bailiff, barrister,
   barrister-at-law, butler, champion, counsel, counselor,
   counselor-at-law, croupier, curator, custodian, deputy, dummy,
   emcee, executive officer, exponent, factor, figurehead,
   friend at court, guardian, housekeeper, intercessor, landreeve,
   lawyer, legal adviser, legal counselor, legal expert,
   legal practitioner, legalist, librarian, lieutenant, locum,
   locum tenens, majordomo, master of ceremonies, mouthpiece,
   paranymph, pinch hitter, pleader, proctor, procurator, proxy,
   representative, sea lawyer, second in command, secondary,
   self-styled lawyer, seneschal, solicitor, stand-in, steward,
   substitute, supply, surrogate, understudy, utility man, vicar,
   vicar general, vice, vicegerent