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]

Moby Thesaurus II by Grady Ward, 1.0:

46 Moby Thesaurus words for "simplification":
   allegorization, clarification, cracking, decipherment, decoding,
   demonstration, demythologization, disentanglement, disinvolvement,
   distillation, easing, editing, elucidation, emendation,
   enlightenment, euhemerism, exegesis, exemplification, expediting,
   expedition, explanation, explication, exposition, expounding,
   facilitation, hastening, illumination, illustration, light,
   narrowing, purification, quickening, rationale, reason, refinement,
   simplifying, smoothing, solution, speeding, streamlining,
   stripping, stripping down, uncluttering, unlocking, unscrambling,
   unsnarling