The Collaborative International Dictionary of English v.0.48:

Neutralization \Neu`tral*i*za"tion\, n. [Cf. F. neutralisation.]
   1. The act or process of neutralizing, or the state of being
      neutralized.
      [1913 Webster]

   2. (Chem.) The act or process by which an acid and a base are
      combined in such proportions that the resulting compound
      is neutral. See Neutral, a., 4.
      [1913 Webster]

WordNet (r) 3.0 (2006):

neutralization
    n 1: action intended to keep a country politically neutral or
         exclude it from a possible war; "the neutralization of
         Belgium" [syn: neutralization, neutralisation]
    2: a chemical reaction in which an acid and a base interact with
       the formation of a salt; with strong acids and bases the
       essential reaction is the combination of hydrogen ions with
       hydroxyl ions to form water [syn: neutralization,
       neutralisation, neutralization reaction, neutralisation
       reaction]
    3: (euphemism) the removal of a threat by killing or destroying
       it (especially in a covert operation or military operation)
       [syn: neutralization, neutralisation]
    4: action intended to nullify the effects of some previous
       action [syn: neutralization, neutralisation,
       counteraction]