The Collaborative International Dictionary of English v.0.48:

Proof \Proof\, n. [OF. prove, proeve, F. preuve, fr. L. proba,
   fr. probare to prove. See Prove.]
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   1. Any effort, process, or operation designed to establish or
      discover a fact or truth; an act of testing; a test; a
      trial.
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            For whatsoever mother wit or art
            Could work, he put in proof.          --Spenser.
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            You shall have many proofs to show your skill.
                                                  --Ford.
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            Formerly, a very rude mode of ascertaining the
            strength of spirits was practiced, called the proof.
                                                  --Ure.
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   2. That degree of evidence which convinces the mind of any
      truth or fact, and produces belief; a test by facts or
      arguments that induce, or tend to induce, certainty of the
      judgment; conclusive evidence; demonstration.
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            I'll have some proof.                 --Shak.
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            It is no proof of a man's understanding to be able
            to confirm whatever he pleases.       --Emerson.
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   Note: Properly speaking, proof is the effect or result of
         evidence, evidence is the medium of proof. Cf.
         Demonstration, 1.
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   3. The quality or state of having been proved or tried;
      firmness or hardness that resists impression, or does not
      yield to force; impenetrability of physical bodies.
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   4. Firmness of mind; stability not to be shaken.
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   5. (Print.) A trial impression, as from type, taken for
      correction or examination; -- called also proof sheet.
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   6. (Math.) A process for testing the accuracy of an operation
      performed. Cf. Prove, v. t., 5.
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   7. Armor of excellent or tried quality, and deemed
      impenetrable; properly, armor of proof. [Obs.] --Shak.
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   Artist's proof, a very early proof impression of an
      engraving, or the like; -- often distinguished by the
      artist's signature.

   Proof reader, one who reads, and marks correction in,
      proofs. See def. 5, above.
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   Syn: Testimony; evidence; reason; argument; trial;
        demonstration. See Testimony.
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