The Collaborative International Dictionary of English v.0.48:

Idealization \I*de`al*i*za"tion\, n.
   1. The act or process of idealizing.
      [1913 Webster]

   2. (Fine Arts) The representation of natural objects, scenes,
      etc., in such a way as to show their most important
      characteristics; the study of the ideal.
      [1913 Webster]

   3. A defense mechanism that splits something one is
      ambivalent about into two representations -- one good and
      one bad. [WordNet sense 1]
      [WordNet 1.5]

   4. something that exists only as an idea. [WordNet sense 2]
      [WordNet 1.5]

   5. a protrayal of something as ideal. [WordNet sense 3]

   Syn: glorification.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

idealization
    n 1: a portrayal of something as ideal; "the idealization of
         rural life was very misleading" [syn: idealization,
         idealisation, glorification]
    2: (psychiatry) a defense mechanism that splits something you
       are ambivalent about into two representations--one good and
       one bad [syn: idealization, idealisation]
    3: something that exists only as an idea [syn: idealization,
       idealisation]