The Collaborative International Dictionary of English v.0.48:

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.
      [1913 Webster]

            Artificial conversion of water into ice. --Bacon.
      [1913 Webster]

            The conversion of the aliment into fat. --Arbuthnot.
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   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.
      [1913 Webster]

   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.
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            Or bring my action of conversion
            And trover for my goods.              --Hudibras.
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   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.
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   5. (Math.) A change or reduction of the form or value of a
      proposition; as, the conversion of equations; the
      conversion of proportions.
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   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.
          [1913 Webster]

   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.
      [1913 Webster]

            He oft
            Frequented their assemblies, . . . and to them
            preached
            Conversion and repentance, as to souls
            In prison under judgments imminent.   --Milton.
      [1913 Webster]

WordNet (r) 3.0 (2006):

conversion
    n 1: an event that results in a transformation [syn:
         conversion, 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: conversion, 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

Moby Thesaurus II by Grady Ward, 1.0:

200 Moby Thesaurus words for "conversion":
   Fabianism, about-face, abstraction, abuse, abuse of office,
   accommodation, adaptation, adjustment, adoption, alteration,
   amelioration, annexation, apostasy, appropriation, architecture,
   assembly, befoulment, betterment, block, blocking, boosting, break,
   building, casting, change, change of heart, changeableness,
   changeover, circumcision, composition, construction,
   constructive change, continuity, conveyance,
   corrupt administration, crafting, craftsmanship, creation,
   cultivation, debasement, defalcation, defection, defense mechanism,
   defilement, degeneration, degenerative change, desecration,
   deterioration, deviation, devising, difference, discontinuity,
   divergence, diversification, diversion, diversity, elaboration,
   embezzlement, erection, evangelization, extraction, extremism,
   fabrication, fashioning, filching, fitting, flip-flop, formation,
   forming, formulation, fouling, framing, fraud, gradual change,
   gradualism, graft, growing, handicraft, handiwork, harvesting,
   improvement, innovation, liberation, lifting, machining, making,
   maladministration, malfeasance, malpractice, malversation,
   manufacture, manufacturing, melioration, meliorism, mental block,
   metamorphosis, milling, mining, misapplication, misappropriation,
   misconduct, misemployment, misfeasance, mishandling, mismanagement,
   misusage, misuse, mitigation, modification, modulation, molding,
   mutation, new birth, new life, novelty, overthrow, peculation,
   permutation, persuasion, perversion, pilferage, pilfering,
   pinching, poaching, pollution, poor stewardship, prefabrication,
   preparation, processing, producing, profanation, progressivism,
   proselytism, proselytization, prostitution, qualification,
   radical change, radical reform, radicalism, raising, re-creation,
   realignment, rebirth, reclamation, redeemedness, redemption,
   redesign, refining, reform, reformation, reformism, regeneration,
   remaking, renewal, repression, reshaping, restructuring, reversal,
   revisionism, revival, revivification, revolution, salvation,
   scrounging, second birth, shaping, shift, shoplifting, smelting,
   snatching, sneak thievery, snitching, spiritual purification,
   stealage, stealing, sublimation, sudden change, suppression,
   swindle, swiping, switch, symbolization, theft, thievery, thieving,
   total change, transformation, transition, transmutation, turn,
   turnabout, turning, upheaval, utopianism, variation, variety,
   violation, violent change, workmanship, worsening



Easton's 1897 Bible Dictionary:

Conversion
   the turning of a sinner to God (Acts 15:3). In a general sense
   the heathen are said to be "converted" when they abandon
   heathenism and embrace the Christian faith; and in a more
   special sense men are converted when, by the influence of divine
   grace in their souls, their whole life is changed, old things
   pass away, and all things become new (Acts 26:18). Thus we speak
   of the conversion of the Philippian jailer (16:19-34), of Paul
   (9:1-22), of the Ethiopian treasurer (8:26-40), of Cornelius
   (10), of Lydia (16:13-15), and others. (See REGENERATION.)


Bouvier's Law Dictionary, Revised 6th Ed (1856):

CONVERSION. torts. the unlawful turning or applying the personal goods of
another to the use of the taker, or of some other person than the, owner; or
the unlawful destroying or altering their nature. Bull. N. P. 44; 6 Mass.
20; 14 Pick. 356; 3 Brod. & Bing. 2; Cro. Eliz. 219 12 Mod. 519; 5 Mass.
104; 6 Shepl. 382; Story, Bailm. Sec. 188, 269, 306; 6 Mass. 422; 2 B. & P.
488; 3 B. & Ald. 702; 11 M. & W. 363; 8 Taunt. 237; 4 Taunt. 24.
     2. When a party takes away or wrongfully assumes the right to goods
which belong to another, it will in general be sufficient evidence of a
conversion but when the original taking was, lawful, as when the party found
the goods, and the detention only is illegal, it is absolutely necessary to
male a demand of the goods, and there must be a refusal to deliver them
before the conversion will, be complete. 1 Ch. Pr. 566; 2 Saund. 47 e, note
1 Ch. Pl. 179; Bac. Ab. Trover, B 1 Com. Dig. 439; 3 Com. Dig. 142; 1 Vin.
Ab. 236; Yelv. 174, n.; 2 East, R. 405; 6 East, R. 540; 4 Taunt. 799 5 Barn.
& Cr. 146; S. C. 11 Eng. C. L. Rep. 185; 3 Bl. Com. 152; 3 Bouv. Inst. n.
3522, et seq. The refusal by a servant to deliver the goods entrusted to him
by his master, is not evidence of a conversion by his master. 5 Hill, 455.
     3. The tortious taking of property is, of itself, a conversion 15 John.
R. 431 and any intermeddling with it, or any exercise of dominion over it,
subversive of the dominion of the owner, or the nature of the bailment, if
it be bailed, is, evidence of a conversion. 1 Nott & McCord, R. 592; 2 Mass.
R. 398; 1 Har. & John. 519; 7 John. R. 254; 10 John. R. 172 14 John. R. 128;
Cro. Eliz. 219; 2 John. Cas. 411. Vide Trover.



Bouvier's Law Dictionary, Revised 6th Ed (1856):

CONVERSION, in equity, The considering of one thing as changed into another;
for example, land will be considered as converted into money, and treated as
such by a court of equity, when the owner has contracted to sell his estate
in which case, if he die before the conveyance, his executors and not his
heirs will be entitled to the money. 2 Vern. 52; S., C. 3 Chan. R. 217; 1
B1. Rep. 129. On the other hand, money is converted into land in a variety
of ways as for example, when a man agrees to buy land, and dies before he
has received the conveyance, the money he was to pay for it will be
considered as converted into lands, and descend to the heir. 1 P. Wms. 176 2
Vern. 227 10 Pet. 563; Bouv. Inst. Index, h.t.