Source : Webster's Revised Unabridged Dictionary (1913)

Ideology \I`de*ol"o*gy\, n. [Ideo- + -logy: cf. F.
   id['e]ologie.]
   1. The science of ideas. --Stewart.

   2. (Metaph.) A theory of the origin of ideas which derives
      them exclusively from sensation.

   Note: By a double blunder in philosophy and Greek,
         id['e]ologie . . . has in France become the name
         peculiarly distinctive of that philosophy of mind which
         exclusively derives our knowledge from sensation. --Sir
         W. Hamilton.

Source : WordNet®

ideology
     n 1: an orientation that characterizes the thinking of a group or
          nation [syn: {political orientation}, {political theory}]
     2: imaginary or visionary theorization