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.
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   2. To convert from spiritual to secular or common use; as, to
      secularize a church, or church property.
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            At the Reformation the abbey was secularized. --W.
                                                  Coxe.
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   3. To make worldly or unspiritual. --Bp. Horsley.
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