The Collaborative International Dictionary of English v.0.48:

Secularize \Sec"u*lar*ize\, v. t. [imp. & p. p. Secularized;
   p. pr. & vb. n. Secularizing.] [Cf. F. s['e]culariser.]
   1. To convert from regular or monastic into secular; as, to
      secularize a priest or a monk.
      [1913 Webster]

   2. To convert from spiritual to secular or common use; as, to
      secularize a church, or church property.
      [1913 Webster]

            At the Reformation the abbey was secularized. --W.
                                                  Coxe.
      [1913 Webster]

   3. To make worldly or unspiritual. --Bp. Horsley.
      [1913 Webster]

WordNet (r) 3.0 (2006):

secularize
    v 1: make secular and draw away from a religious orientation;
         "Ataturk secularized Turkey" [syn: secularize,
         secularise]
    2: transfer from ecclesiastical to civil possession, use, or
       control [syn: desacralize, secularize]