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.]
   [1913 Webster]
   1. Any effort, process, or operation designed to establish or
      discover a fact or truth; an act of testing; a test; a
      trial.
      [1913 Webster]

            For whatsoever mother wit or art
            Could work, he put in proof.          --Spenser.
      [1913 Webster]

            You shall have many proofs to show your skill.
                                                  --Ford.
      [1913 Webster]

            Formerly, a very rude mode of ascertaining the
            strength of spirits was practiced, called the proof.
                                                  --Ure.
      [1913 Webster]

   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.
      [1913 Webster]

            I'll have some proof.                 --Shak.
      [1913 Webster]

            It is no proof of a man's understanding to be able
            to confirm whatever he pleases.       --Emerson.
      [1913 Webster]

   Note: Properly speaking, proof is the effect or result of
         evidence, evidence is the medium of proof. Cf.
         Demonstration, 1.
         [1913 Webster]

   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.
      [1913 Webster]

   4. Firmness of mind; stability not to be shaken.
      [1913 Webster]

   5. (Print.) A trial impression, as from type, taken for
      correction or examination; -- called also proof sheet.
      [1913 Webster]

   6. (Math.) A process for testing the accuracy of an operation
      performed. Cf. Prove, v. t., 5.
      [1913 Webster]

   7. Armor of excellent or tried quality, and deemed
      impenetrable; properly, armor of proof. [Obs.] --Shak.
      [1913 Webster]

   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.
      [1913 Webster]

   Syn: Testimony; evidence; reason; argument; trial;
        demonstration. See Testimony.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Proof \Proof\, a.
   [1913 Webster]
   1. Used in proving or testing; as, a proof load, or proof
      charge.
      [1913 Webster]

   2. Firm or successful in resisting; as, proof against harm;
      waterproof; bombproof.
      [1913 Webster]

            I . . . have found thee
            Proof against all temptation.         --Milton.
      [1913 Webster]

            This was a good, stout proof article of faith.
                                                  --Burke.
      [1913 Webster]

   3. Being of a certain standard as to strength; -- said of
      alcoholic liquors.
      [1913 Webster]

   Proof charge (Firearms), a charge of powder and ball,
      greater than the service charge, fired in an arm, as a gun
      or cannon, to test its strength.

   Proof impression. See under Impression.

   Proof load (Engin.), the greatest load than can be applied
      to a piece, as a beam, column, etc., without straining the
      piece beyond the elastic limit.

   Proof sheet. See Proof, n., 5.

   Proof spirit (Chem.), a strong distilled liquor, or mixture
      of alcohol and water, containing not less than a standard
      amount of alcohol. In the United States "proof spirit is
      defined by law to be that mixture of alcohol and water
      which contains one half of its volume of alcohol, the
      alcohol when at a temperature of 60[deg] Fahrenheit being
      of specific gravity 0.7939 referred to water at its
      maximum density as unity. Proof spirit has at 60[deg]
      Fahrenheit a specific gravity of 0.93353, 100 parts by
      volume of the same consisting of 50 parts of absolute
      alcohol and 53.71 parts of water," the apparent excess of
      water being due to contraction of the liquids on mixture.
      In England proof spirit is defined by Act 58, George III.,
      to be such as shall at a temperature of 51[deg] Fahrenheit
      weigh exactly the 12/13 part of an equal measure of
      distilled water. This contains 49.3 per cent by weight, or
      57.09 by volume, of alcohol. Stronger spirits, as those of
      about 60, 70, and 80 per cent of alcohol, are sometimes
      called second, third, and fourth proof spirits
      respectively.

   Proof staff, a straight-edge used by millers to test the
      flatness of a stone.

   Proof stick (Sugar Manuf.), a rod in the side of a vacuum
      pan, for testing the consistency of the sirup.

   Proof text, a passage of Scripture used to prove a
      doctrine.
      [1913 Webster]

WordNet (r) 3.0 (2006):

proof
    adj 1: (used in combination or as a suffix) able to withstand;
           "temptation-proof"; "childproof locks"
    n 1: any factual evidence that helps to establish the truth of
         something; "if you have any proof for what you say, now is
         the time to produce it" [syn: proof, cogent evidence]
    2: a formal series of statements showing that if one thing is
       true something else necessarily follows from it
    3: a measure of alcoholic strength expressed as an integer twice
       the percentage of alcohol present (by volume)
    4: (printing) an impression made to check for errors [syn:
       proof, test copy, trial impression]
    5: a trial photographic print from a negative
    6: the act of validating; finding or testing the truth of
       something [syn: validation, proof, substantiation]
    v 1: make or take a proof of, such as a photographic negative,
         an etching, or typeset
    2: knead to reach proper lightness; "proof dough"
    3: read for errors; "I should proofread my manuscripts" [syn:
       proofread, proof]
    4: activate by mixing with water and sometimes sugar or milk;
       "proof yeast"
    5: make resistant (to harm); "proof the materials against
       shrinking in the dryer"

Moby Thesaurus II by Grady Ward, 1.0:

278 Moby Thesaurus words for "proof":
   Christophany, Ditto copy, Photostat, Satanophany, Xerox,
   Xerox copy, absolute indication, account, acid test, acquaintance,
   affirmation, airtight, ammunition, angelophany, announcement,
   appearance, argument, assay, attestation, authentication, avatar,
   backing, backing up, ballproof, basis for belief, bearing out,
   blank determination, blue, blue book, blueprint, body of evidence,
   bolstering, bombproof, briefing, bring out, brouillon, bulletin,
   bulletproof, burden of proof, burglarproof, buttressing,
   certification, chain of evidence, circumstantiation, clue,
   cold-type proof, color proof, communication, communique,
   computer proof, conclusive evidence, confirmation, contact print,
   corroboration, corroboratory evidence, corrosionproof, criterion,
   crucial test, crucible, damning evidence, dampproof, data, datum,
   deduction, deductive reasoning, demonstration, determination,
   directory, disclosure, discourse, discourse of reason,
   discursive reason, dispatch, dissemination, docimasy, document,
   documentation, embodiment, engrave, enlargement, enlightenment,
   epiphany, essay, establishment, evidence, evincement, exhibit,
   expression, fact, facts, factual information, familiarization,
   feeling out, fire-resisting, fireproof, first draft, flameproof,
   foolproof, fortification, foundry proof, galley, galley proof, gen,
   general information, get out, ground, grounds, grounds for belief,
   guidebook, handout, hard information, hectograph, hectograph copy,
   hermetic, holeproof, impenetrable, impervious, impervious to,
   impregnable, impress, impression, imprint, incarnation,
   incidental information, incontrovertible evidence, indication,
   indisputable evidence, induction, inductive reasoning, info,
   information, instruction, insulate, intelligence, ironclad proof,
   issue, item of evidence, kiteflying, knowledge, leakproof, light,
   logical thought, manifestation, mark, material grounds,
   materialization, measure, mention, message, mimeograph,
   mimeograph copy, multigraph, muniments, mute witness, negative,
   noiseproof, notice, notification, offprint, onus, onus probandi,
   ordeal, overprint, page proof, philosophy, photocopy, photograph,
   photostatic copy, piece of evidence, plate proof, pneumatophany,
   positive, premises, presentation, press proof, print, probation,
   progressive proof, promotional material, proof against,
   proof before letter, proof sheet, protective, prove, proving,
   proving out, publication, publicity, publish, pull, pull a proof,
   punctureproof, put out, put to bed, put to press, ratification,
   ratiocination, rationalism, rationality, rationalization,
   rationalizing, reason, reason to believe, reasonableness,
   reasoning, reinforcement, reissue, release, relevant fact, report,
   reprint, repro proof, resistant, revelation, revise, rough draft,
   rough sketch, run, run off, rustproof, settlement, shatterproof,
   shellproof, sidelight, sign, slip, sophistry, sounding out,
   soundproof, specious reasoning, stamp, standard, stat, statement,
   stone proof, strengthening, strike, strong, substantiation,
   support, supporting evidence, sure sign, sweet reason, symptom,
   tempered, test, test case, testament, testimonial, testimony,
   the dope, the goods, the know, the scoop, theophany, tight, token,
   touchstone, tough, transmission, trial, trial impression, try,
   undergirding, unmistakable sign, validation, vandyke, verification,
   waterproof, watertight, weatherproof, wherefore, white book,
   white paper, why, whyfor, witness, word



The Free On-line Dictionary of Computing (30 December 2018):

proof

   1.  A finite sequence of well-formed formulas, F1,
   F2, ... Fn, where each Fi either is an axiom, or follows by
   some rule of inference from some of the previous F's, and Fn
   is the statement being proved.

   See also proof theory.

   2. A left-associative natural language parser by Craig
   R. Latta .  Ported to Decstation
   3100, Sun-4.

   (ftp://scam.berkeley.edu/pub/src/local/proof/).

   E-mail: .  Mailing list:
   proof-requestf@xcf.berkeley.edu (Subject: add me).

   (1994-11-29)


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

PROOF, practice. The conviction or persuasion of the mind of a judge or
jury, by the exhibition of evidence, of the reality of a fact alleged: as,
to prove, is to determine or persuade that a thing does or does not exist. 8
Toull. n. 2; Ayl. Parerg. 442; 2 Phil. Ev. 44, n, a. Proof is the perfection
of evidence, for without evidence there is no proof, although, there may be
evidence which does not amount to proof: for example, a man is found
murdered at a spot where another had been seen walking but a short time
before, this fact would be evidence to show that the latter was the
murderer, but, standing alone, would be very far from proof of it.
     2. Ayliffe defines judicial proof to be a clear and evident declaration
or demonstration, of a matter which was before doubtful, conveyed in a
judicial manner by fit and proper arguments, and likewise by all other legal
methods; first, by proper arguments, such as conjectures, presumptions,
indicia, and other adminicular ways and means; and, secondly, by legal
method, or methods according to law, such as witnesses, public instruments,
end the like. Parerg. 442 Aso. & Man. Inst. B. 3, t. 7.



The Devil's Dictionary (1881-1906):

PROOF, n.  Evidence having a shade more of plausibility than of
unlikelihood.  The testimony of two credible witnesses as opposed to
that of only one.