The Collaborative International Dictionary of English v.0.48:

Manipulation \Ma*nip`u*la"tion\, n. [Cf. F. manipulation.]
   1. The act or process of manipulating, or the state of being
      manipulated; the act of handling work by hand; use of the
      hands, in an artistic or skillful manner, in science or
      art.
      [1913 Webster]

            Manipulation is to the chemist like the external
            senses to the mind. --Whewell.
      [1913 Webster]

   2. The use of the hands in mesmeric operations.
      [1913 Webster]

   3. Artful management; as, the manipulation of political
      bodies; sometimes, a management or treatment for purposes
      of deception or fraud.
      [1913 Webster]

WordNet (r) 3.0 (2006):

manipulation
    n 1: exerting shrewd or devious influence especially for one's
         own advantage; "his manipulation of his friends was
         scandalous" [syn: manipulation, use]
    2: the action of touching with the hands (or the skillful use of
       the hands) or by the use of mechanical means [syn:
       handling, manipulation]