The Collaborative International Dictionary of English v.0.48:

Sterilization \Ster`il*i*za"tion\, n. (Biol.)
   The act or process of sterilizing, or rendering sterile;
   also, the state of being sterile.
   [1913 Webster]

WordNet (r) 3.0 (2006):

sterilization
    n 1: the act of making an organism barren or infertile (unable
         to reproduce) [syn: sterilization, sterilisation]
    2: the procedure of making some object free of live bacteria or
       other microorganisms (usually by heat or chemical means)
       [syn: sterilization, sterilisation]