demagnetize

from WordNet (r) 3.0 (2006)

demagnetize
    v 1: erase (a magnetic storage device) [syn: {demagnetize},
         {demagnetise}]
    2: make nonmagnetic; take away the magnetic properties (of);
       "demagnetize the iron shavings"; "they degaussed the ship"
       [syn: {demagnetize}, {demagnetise}, {degauss}] [ant:
       {magnetise}, {magnetize}]

from The Collaborative International Dictionary of English v.0.48

Demagnetize \De*mag"net*ize\, v. t.
   1. To deprive of magnetic properties; to render nonmagnetic.
      See {Magnetize}.
      [1913 Webster]

            If the bar be rapidly magnetized and demagnetized.
                                                  --Am. Cyc.
      [1913 Webster]

   2. To free from mesmeric influence; to demesmerize. [archaic]
      [1913 Webster +PJC] -- {De*mag`net*i*za"tion}, n. --
      {De*mag"net*i`zer}, n.
      [1913 Webster]