The Collaborative International Dictionary of English v.0.48:

Simplify \Sim"pli*fy\, v. t. [imp. & p. p. Simplified; p. pr.
   & vb. n. Simplifying.] [Cf. F. simplifier, LL.
   simplificare. See Simple, and -fy.]
   To make simple; to make less complex; to make clear by giving
   the explanation for; to show an easier or shorter process for
   doing or making.
   [1913 Webster]

         The collection of duties is drawn to a point, and so
         far simplified.                          --A. Hamilton.
   [1913 Webster]

         It is important, in scientific pursuits, to be caitious
         in simplifying our deductions.           --W.
                                                  Nicholson.
   [1913 Webster]

WordNet (r) 3.0 (2006):

simplify
    v 1: make simpler or easier or reduce in complexity or extent;
         "We had to simplify the instructions"; "this move will
         simplify our lives" [ant: complicate, perplex]