Source : Webster's Revised Unabridged Dictionary (1913)

Conversion \Con*ver"sion\, n. [L. conversio: cf. F. conversion.
   See {Convert}.]
   1. The act of turning or changing from one state or condition
      to another, or the state of being changed; transmutation;
      change.

            Artificial conversion of water into ice. --Bacon.

            The conversion of the aliment into fat. --Arbuthnot.

   2. The act of changing one's views or course, as in passing
      from one side, party, or from of religion to another;
      also, the state of being so changed. ``Conversion to
      Christianity.'' --Prescott.

   3. (Law) An appropriation of, and dealing with the property
      of another as if it were one's own, without right; as, the
      conversion of a horse.

            Or bring my action of conversion And trover for my
            goods.                                --Hudibras.

   4. (Logic) The act of interchanging the terms of a
      proposition, as by putting the subject in the place of the
      predicate, or the contrary.

   5. (Math.) A change or reduction of the form or value of a
      proposition; as, the conversion of equations; the
      conversion of proportions.

   6. (Mil.)
      (a) A change of front, as a body of troops attacked in the
          flank.
      (b) A change of character or use, as of smoothbore guns
          into rifles.

   7. (Theol.) A spiritual and moral change attending a change
      of belief with conviction; a change of heart; a change
      from the service of the world to the service of God; a
      change of the ruling disposition of the soul, involving a
      transformation of the outward life.

            He oft Frequented their assemblies, . . . and to
            them preached Conversion and repentance, as to souls
            In prison under judgments imminent.   --Milton.

Source : WordNet®

conversion
     n 1: an event that results in a transformation [syn: {transition},
           {changeover}]
     2: a change in the units or form of an expression: "conversion
        from Fahrenheit to Centigrade"
     3: a successful free throw or try for point after a touchdown
     4: a spiritual enlightenment causing a person to lead a new
        life [syn: {rebirth}, {spiritual rebirth}]
     5: (psychiatry) a defense mechanism represses emotional
        conflicts which are then converted into physical symptoms
        that have no organic basis
     6: a change of religion; "his conversion to the Catholic faith"
     7: interchange of subject and predicate of a proposition
     8: act of exchanging one type of money or security for another
     9: the act of changing from one use or function or purpose to
        another