Source : Webster's Revised Unabridged Dictionary (1913)

Ideation \I`de*a"tion\, n.
   The faculty or capacity of the mind for forming ideas; the
   exercise of this capacity; the act of the mind by which
   objects of sense are apprehended and retained as objects of
   thought.

         The whole mass of residua which have been accumulated .
         . . all enter now into the process of ideation. --J. D.
                                                  Morell.

Source : WordNet®

ideation
     n : the process of forming and relating ideas