The Collaborative International Dictionary of English v.0.48:

Sterilize \Ster"il*ize\, v. t. [imp. & p. p. Sterilized; p.
   pr. & vb. n. Sterilizing.] [Cf. F. st['e]riliser.]
   1. To make sterile or unproductive; to impoverish, as land;
      to exhaust of fertility. [R.] "Sterilizing the earth."
      --Woodward.
      [1913 Webster]

   2. (Biol.) To deprive of the power of reproducing; to render
      incapable of germination or fecundation; to make sterile.

   3. (Microbiology, Medicine) To destroy all spores or germs in
      (an organic fluid or mixture) or on (a medical
      instrument), as by heat, so as to prevent contamination by
      bacteria or other organisms. A common method of
      sterilization in laboratories and medical facilities is to
      heat a liquid sample or an instrument in an autoclave.
      [1913 Webster +PJC]

   4. To destroy all spores or germs on (a surface) by wetting
      with an antiseptic liquid, such as an alcoholic solution.
      [PJC]

WordNet (r) 3.0 (2006):

sterilize
    v 1: make free from bacteria [syn: sterilize, sterilise]
    2: make infertile; "in some countries, people with genetically
       transmissible disabilites are sterilized" [syn: sterilize,
       sterilise, desex, unsex, desexualize, desexualise,
       fix]

Moby Thesaurus II by Grady Ward, 1.0:

36 Moby Thesaurus words for "sterilize":
   alter, antisepticize, autoclave, boil, castrate, change,
   chlorinate, clean, cleanse, decontaminate, delouse, demasculinize,
   depurate, desex, desexualize, devitalize, disinfect, effeminize,
   emasculate, enervate, etiolate, exhaust, fix, fumigate, geld,
   hygienize, mutilate, neuter, pasteurize, purify, sanitate,
   sanitize, spay, unman, unnerve, unsex