The Collaborative International Dictionary of English v.0.48:

Simplification \Sim`pli*fi*ca"tion\, n. [Cf. F. simplification.]
   The act of simplifying. --A. Smith.
   [1913 Webster]

WordNet (r) 3.0 (2006):

simplification
    n 1: an explanation that omits superfluous details and reduces
         complexity
    2: elimination of superfluous details
    3: the act of reducing complexity [syn: reduction,
       simplification]