The Collaborative International Dictionary of English v.0.48:

neuter \neu"ter\, v. t.
   To render incapable of sexual reproduction; to remove or
   alter the sexual organs so as to make infertile; to alter; to
   fix; to desex; -- in male animals, to castrate; in female
   animals, to spay.
   [PJC]

The Collaborative International Dictionary of English v.0.48:

Castrate \Cas"trate\, v. t. [imp. & p. p. Castrated; p. pr. &
   vb. n. Castrating.] [L. castrarus, p; p. of castrare to
   castrate, asin to Skr. [,c]astra knife.]
   1. To deprive of the testicles; to emasculate; to geld; to
      alter.
      [1913 Webster]

   2. To cut or take out; esp. to remove anything erroneous, or
      objectionable from, as the obscene parts of a writing; to
      expurgate.
      [1913 Webster]

            My . . . correspondent . . . has sent me the
            following letter, which I have castrated in some
            places.                               --Spectator.
      [1913 Webster]

WordNet (r) 3.0 (2006):

castrate
    n 1: a man who has been castrated and is incapable of
         reproduction; "eunuchs guarded the harem" [syn: eunuch,
         castrate]
    v 1: deprive of strength or vigor; "The Senate emasculated the
         law" [syn: emasculate, castrate]
    2: edit by omitting or modifying parts considered indelicate;
       "bowdlerize a novel" [syn: bowdlerize, bowdlerise,
       expurgate, castrate, shorten]
    3: remove the testicles of a male animal [syn: emasculate,
       castrate, demasculinize, demasculinise]
    4: remove the ovaries of; "Is your cat spayed?" [syn: alter,
       neuter, spay, castrate]