The Collaborative International Dictionary of English v.0.48:

Director \Di*rect"or\, n. [Cf. F. directeur.]
   1. One who, or that which, directs; one who regulates,
      guides, or orders; a manager or superintendent.
      [1913 Webster]

            In all affairs thou sole director.    --Swift.
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   2. One of a body of persons appointed to manage the affairs
      of a company or corporation; as, the directors of a bank,
      insurance company, or railroad company.
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            What made directors cheat in South-Sea year? --Pope.
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   3. (Mech.) A part of a machine or instrument which directs
      its motion or action.
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   4. (Surg.) A slender grooved instrument upon which a knife is
      made to slide when it is wished to limit the extent of
      motion of the latter, or prevent its injuring the parts
      beneath.
      [1913 Webster]

WordNet (r) 3.0 (2006):

director
    n 1: someone who controls resources and expenditures [syn:
         director, manager, managing director]
    2: member of a board of directors
    3: someone who supervises the actors and directs the action in
       the production of a show [syn: director, theater
       director, theatre director]
    4: the person who directs the making of a film [syn: film
       director, director]
    5: the person who leads a musical group [syn: conductor,
       music director, director]