The Collaborative International Dictionary of English v.0.48:

Dichotomize \Di*chot"o*mize\, v. i.
   To separate into two parts; to branch dichotomously; to
   become dichotomous.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Dichotomize \Di*chot"o*mize\, v. t. [imp. & p. p.
   Dichotomized; p. pr. & vb. n. Dichotomizing.] [See
   Dichotomous.]
   1. To cut into two parts; to part into two divisions; to
      divide into pairs; to bisect. [R.]
      [1913 Webster]

            The apostolical benediction dichotomizes all good
            things into grace and peace.          --Bp. Hall.
      [1913 Webster]

   2. (Astron.) To exhibit as a half disk. See Dichotomy, 3.
      "[The moon] was dichotomized." --Whewell.
      [1913 Webster]

WordNet (r) 3.0 (2006):

dichotomize
    v 1: divide into two opposing groups or kinds [syn:
         dichotomize, dichotomise]