The Collaborative International Dictionary of English v.0.48:

Conviction \Con*vic"tion\ (k[o^]n*v[i^]k"sh[u^]n), n. [L.
   convictio proof: cf. F. conviction conviction (in sense 3 &
   4). See Convict, Convince.]
   1. The act of convicting; the act of proving, finding, or
      adjudging, guilty of an offense.
      [1913 Webster]

            The greater certainty of conviction and the greater
            certainty of punishment.              --Hallam.
      [1913 Webster]

   2. (Law) A judgment of condemnation entered by a court having
      jurisdiction; the act or process of finding guilty, or the
      state of being found guilty of any crime by a legal
      tribunal.
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            Conviction may accrue two ways.       --Blackstone.
      [1913 Webster]

   3. The act of convincing of error, or of compelling the
      admission of a truth; confutation.
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            For all his tedious talk is but vain boast,
            Or subtle shifts conviction to evade. --Milton.
      [1913 Webster]

   4. The state of being convinced or convicted; strong
      persuasion or belief; especially, the state of being
      convicted of sin, or by one's conscience.
      [1913 Webster]

            To call good evil, and evil good, against the
            conviction of their own consciences.  --Swift.
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            And did you presently fall under the power of this
            conviction?                           --Bunyan.

   Syn: Conviction; persuasion.

   Usage: Conviction respects soley matters of belief or faith;
          persuasion respects matters of belief or practice.
          Conviction respects our most important duties;
          persuasion is frequently applied to matters of
          indifference. --Crabb. -- Conviction is the result of
          the [operation of the] understanding; persuasion, of
          the will. Conviction is a necessity of the mind,
          persuasion an acquiescence of the inclination. --C. J.
          Smith. -- Persuasion often induces men to act in
          opposition to their conviction of duty.
          [1913 Webster]

WordNet (r) 3.0 (2006):

conviction
    n 1: an unshakable belief in something without need for proof or
         evidence [syn: conviction, strong belief, article of
         faith]
    2: (criminal law) a final judgment of guilty in a criminal case
       and the punishment that is imposed; "the conviction came as
       no surprise" [syn: conviction, judgment of conviction,
       condemnation, sentence] [ant: acquittal]

Moby Thesaurus II by Grady Ward, 1.0:

92 Moby Thesaurus words for "conviction":
   anathematizing, arrogance, aspiration, assumption, assurance,
   assured faith, assuredness, belief, censure, certainty, certitude,
   cheerful expectation, cocksureness, condemnation, confidence,
   confidentness, courage, damnation, death sentence, death warrant,
   denouncement, denunciation, dependence, desire, doctrine, dogma,
   doom, doomed hope, excommunication, expectation, eye,
   fair prospect, faith, feeling, fervent hope, fixed opinion,
   good cheer, good hope, great expectations, guilty verdict,
   high hopes, hope, hopeful prognosis, hopefulness, hopes, hoping,
   hoping against hope, hubris, implicit belief, judgment,
   mature judgment, mind, opinion, overconfidence, oversureness,
   overweening, overweeningness, persuasion, poise, pomposity,
   position, positiveness, prayerful hope, presumption, pride,
   promise, proscription, prospect, prospects, rap, reliance,
   sanguine expectation, security, self-assurance, self-confidence,
   self-importance, self-reliance, sentence, sentiment,
   settled belief, settled judgment, staunch belief, steadfast faith,
   subjective certainty, sureness, surety, tenet, trust,
   unshaken confidence, verdict of guilty, view, well-grounded hope



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

CONVICTION, practice. A condemnation. In its most extensive sense this word
signifies the giving judgment against a defendant, whether criminal or
civil. In a more limited sense, it means, the judgment given against the
criminal. And in its most restricted sense it is a record of the summary
proceedings upon any penal statute before one or more justices of the peace,
or other persons duly authorized, in a case where the offender has been
convicted and sentenced: this last is usually termed a summary conviction.
     2. As summary. convictions have been introduced in derogation of the
common law, and operate to the exclusion of trial by jury, the courts have
required that the strict letter of the statute should be observed 1 Burr.
Rep. 613 and that the magistrates should have been guided by rules similar
to those adopted by the common law, in criminal prosecution, and founded in
natural justice; unless when the statute dispenses with the form of stating
them.
     3. The general rules in relation to convictions are, first, it must be
under the hand and seal of the magistrate before whom it is taken; secondly,
it must be in the present tense, but this, perhaps, ought to extend only to
the judgment; thirdly, it must be certain; fourthly, although it is well to
lay the offence to be contra pacem, this is not indispensable; fifthly, a
conviction cannot be good in part and bad in part.
     4. A conviction usually consists of six parts; first, the information;
which should contain, 1. The day when it was taken. 2. The place where it
was taken.  3. The name of the informer. 4. The name and style of the
justice or justices to whom it was given. 5. The name of the offender. 6.
The time of committing the offence. 7. The place where the offence was
committed. 8. An exact description of the offence.
     5. Secondly, the summons.
     6. Thirdly, the appearance or non-appearance of the defendant.
     7. Fourthly, his defence or confessions.
     8. Fifthly, the evidence. Dougl. 469; 2 Burr. 1163; 4 Burr. 2064.
     9. Sixthly, the judgment or adjudication, which should state, 1. That
the defendant is convicted. 2. The forfeiture or penalty. Vide Bosc. on
Conviction; Espinasse on Penal Actions; 4 Dall. 266; 3 Yeates, 475; 1
Yeates, 471. As to the effect of a conviction as evidence in a civil case,
see 1 Phil. Ev. 259; 8 Bouv. Inst. 3183.