The Collaborative International Dictionary of English v.0.48:

Commission \Com*mis"sion\, n. [F., fr. L. commissio. See
   Commit.]
   1. The act of committing, doing, or performing; the act of
      perpetrating.
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            Every commission of sin introduces into the soul a
            certain degree of hardness.           --South.
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   2. The act of intrusting; a charge; instructions as to how a
      trust shall be executed.
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   3. The duty or employment intrusted to any person or persons;
      a trust; a charge.
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   4. A formal written warrant or authority, granting certain
      powers or privileges and authorizing or commanding the
      performance of certain duties.
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            Let him see our commission.           --Shak.
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   5. A certificate conferring military or naval rank and
      authority; as, a colonel's commission.
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   6. A company of persons joined in the performance of some
      duty or the execution of some trust; as, the interstate
      commerce commission.
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            A commission was at once appointed to examine into
            the matter.                           --Prescott.
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   7. (Com.)
      (a) The acting under authority of, or on account of,
          another.
      (b) The thing to be done as agent for another; as, I have
          three commissions for the city.
      (c) The brokerage or allowance made to a factor or agent
          for transacting business for another; as, a commission
          of ten per cent on sales. See Del credere.
          [1913 Webster]

   Commission of array. (Eng. Hist.) See under Array.

   Commission of bankruptcy, a commission appointing and
      empowering certain persons to examine into the facts
      relative to an alleged bankruptcy, and to secure the
      bankrupt's lands and effects for the creditors.

   Commission of lunacy, a commission authorizing an inquiry
      whether a person is a lunatic or not.

   Commission merchant, one who buys or sells goods on
      commission, as the agent of others, receiving a rate per
      cent as his compensation.

   Commission officer or Commissioned officer, (Mil.), one
      who has a commission, in distinction from a
      noncommissioned or warrant officer.

   Commission of the peace, a commission under the great seal,
      constituting one or more persons justices of the peace.
      [Eng.]

   on commission, paid partly or completely by collecting as a
      commision a portion of the sales that one makes.

   out of commission, not operating properly; out of order.

   To put a vessel into commission (Naut.), to equip and man a
      government vessel, and send it out on service after it has
      been laid up; esp., the formal act of taking command of a
      vessel for service, hoisting the flag, reading the orders,
      etc.

   To put a vessel out of commission (Naut.), to detach the
      officers and crew and retire it from active service,
      temporarily or permanently.

   To put the great seal into commission or To put the
   Treasury into commission, to place it in the hands of a
      commissioner or commissioners during the abeyance of the
      ordinary administration, as between the going out of one
      lord keeper and the accession of another. [Eng.]

   The United States Christian Commission, an organization
      among the people of the North, during the Civil War, which
      afforded material comforts to the Union soldiers, and
      performed services of a religious character in the field
      and in hospitals.

   The United States Sanitary Commission, an organization
      formed by the people of the North to cooperate with and
      supplement the medical department of the Union armies
      during the Civil War.

   Syn: Charge; warrant; authority; mandate; office; trust;
        employment.
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Bouvier's Law Dictionary, Revised 6th Ed (1856):

COMMISSION MERCHANT. One employed to sell goods for another on commission; a
factor. He is sometimes called. a consignee, (q.v.) and the goods he
receives are a consignment. 1 Bouv. Inst. n. 1013.