The Collaborative International Dictionary of English v.0.48:

Operator \Op"er*a`tor\, n. [L.]
   1. One who, or that which, operates or produces an effect.
      [1913 Webster]

   2. (Surg.) One who performs some act upon the human body by
      means of the hand, or with instruments.
      [1913 Webster]

   3. A dealer in stocks or any commodity for speculative
      purposes; a speculator. [Brokers' Cant]
      [1913 Webster]

   4. (Math.) The symbol that expresses the operation to be
      performed; -- called also facient.
      [1913 Webster]

   5. A person who operates a telephone switchboard.
      [PJC]

   6. A person who schemes and maneuvers adroitly or deviously
      to achieve his/her purposes.
      [PJC]

The Collaborative International Dictionary of English v.0.48:

Facient \Fa"cient\, n. [L. faciens, -- entis, p. pr. of facere
   to make, do. See Fact.]
   1. One who does anything, good or bad; a doer; an agent.
      [Obs.] --Bp. Hacket.
      [1913 Webster]

   2. (Mach.)
      (a) One of the variables of a quantic as distinguished
          from a coefficient.
      (b) The multiplier.
          [1913 Webster]

   Note: The terms facient, faciend, and factum, may imply that
         the multiplication involved is not ordinary
         multiplication, but is either some specified operation,
         or, in general, any mathematical operation. See
         Multiplication.
         [1913 Webster]