from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun The evidence or argument that compels the mind to accept an assertion as true.
  • noun The validation of a proposition by application of specified rules, as of induction or deduction, to assumptions, axioms, and sequentially derived conclusions.
  • noun A statement or argument used in such a validation.
  • noun Convincing or persuasive demonstration.
  • noun The state of being convinced or persuaded by consideration of evidence.
  • noun Determination of the quality of something by testing; trial.
  • noun The establishment of the truth or falsity of an allegation by evidence.
  • noun The evidence offered in support of or in contravention of an allegation.
  • noun The alcoholic strength of a liquor, expressed by a number that is twice the percentage by volume of alcohol present.
  • noun A trial sheet of printed material that is made to be checked and corrected.
  • noun A trial impression of a plate, stone, or block taken at any of various stages in engraving.
  • noun A trial photographic print.
  • noun Any of a limited number of newly minted coins or medals struck as specimens and for collectors from a new die on a polished planchet.
  • noun Archaic Proven impenetrability.
  • adjective Fully or successfully resistant; impervious. Often used in combination.
  • adjective Of standard alcoholic strength.
  • adjective Used to proofread or correct typeset copy.
  • intransitive verb To make a trial impression of (printed or engraved matter).
  • intransitive verb To proofread (copy).
  • intransitive verb To activate (dormant dry yeast) by adding water.
  • intransitive verb To work (dough) into proper lightness.
  • intransitive verb To treat so as to make resistant.
  • intransitive verb Printing To proofread.
  • intransitive verb To become properly light for cooking.

from The Century Dictionary.

  • noun Any effort, act, or operation made for the purpose of ascertaining any truth or fact; a test; a trial: as, to make proof of a person's trustworthiness or courage.
  • noun Evidence and argumentation putting the conclusion beyond reasonable doubt; demonstration, perfect or imperfect.
  • noun A thing proved or tried; truth or knowledge gathered by experience; experience.
  • noun The state of having been tested and approved; firmness, hardness, or impenetrability: specifically applied to arms or armor of defense, to note that they have been duly tested and are impenetrable.
  • noun In law: The convincing effect of evidence; the manifestation of the truth of a proposition by presenting the reasons for assenting to it; such an array of evidence as should determine the judgment of the tribunal in regard to a matter of fact.
  • noun plural In equity practice, the instruments of evidence in their documentary form, as depositions, deeds, etc., received in a cause.
  • noun The presentation of sufficient evidence: as, the burden of proof lies with the plaintiff.
  • noun In Scots law, the taking of evidence by a judge upon an issue framed in pleading.
  • noun A test applied to manufactured articles or to natural substances prepared for use; hence, the state of that which has undergone this test, or is capable of undergoing it satisfactorily. Compare armor of proof.
  • noun 7. In alcoholic liquors, the degree of strength which gives a specific gravity of 0.920. See II., 2.
  • noun In printing, a trial impression from composed type, taken for correction.
  • noun In engraving and etching, an impression taken from an engraved plate to show its state during the progress of executing it; also, an early and superior impression, or one of a limited number, taken before the title or inscription is engraved on the plate, and known as proof before letter.
  • noun In numismatics, any early impression struck at the mint from a coin-die used for producing the current coins of the realm.
  • noun In bookbinding, the rough uncut edges of the shorter leaves of a trimmed book, which prove that the book has not been cut down too much.
  • noun In arithmetic, an operation serving to check the accuracy of the calculation.
  • noun Proof independent of experience.
  • noun Synonyms Experiment, essay, ordeal.
  • noun Testimony, etc. (see evidence and inference), demonstration, certification.
  • Impenetrable; able to resist, physically or morally: as, water-proof, fire-proof, shot-proof, bribe-proof: often followed by to or against before the thing resisted.


from The American Heritage® Dictionary of the English Language, 4th Edition

[Middle English prove, preve, from Anglo-Norman prove and from Old French prueve, both from Late Latin proba, from Latin probāre, to prove; see prove.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Middle English proof, from Old French prove, from Late Latin proba ("a proof"), from Latin probare ("to prove"); see prove.


Help support Wordnik (and make this page ad-free) by adopting the word proof.


  • That is so funny about your selecting the squirrel proof feeder, and I can agree, some are more *proof* than others!

    At The Gate « Fairegarden 2009

  • However, when it comes to attempting to understand the deep structure of classical proof systems (and in particular, when two derivations that differ in some superficial syntactic way are really different ways to represent the one underlying ˜proof™) it is enlightening to think of classical logic as formed by a basic substructural logic, in which extra structural rules are imposed as additions.

    Substructural Logics Restall, Greg 2008

  • ‡ An apparently intact hymen is valued in some cultures as proof of virginity in a bride; this “proof, ” however, is not accurate.

    hymen 2002

  • A proof taken of the whole galley at once is called a _galley proof_.

    Up To Date Business Home Study Circle Library Series (Volume II.) Various

  • Here, then, we are told that proof of the occasional transmission of mutilations would be sufficient to establish the fact, but on p. 267 we find that no single fact is known which really proves that acquired characters can be transmitted, "_for the ascertained facts which seem to point to the transmission of artificially produced diseases cannot be considered as proof_" [Italics mine.]

    Essays on Life, Art and Science Samuel Butler 1868

  • But I say, by authority of the Master, that _the highest proof, the absolute proof, the perfect proof_, of the FACTS as to _who God is, and what he does_, and the

    Slavery Ordained of God 1839

  • The strength of spirit stronger than _proof_ or _over proof_, as it is termed by the revenue officers, is indicated by the bulk of water necessary to reduce a given volume of it, to the legal standard spirit, denominated _proof_ -- namely; if one gallon of water be required to bring twenty gallons of brandy, rum, or any other spirit, to proof, that spirit is said to be _1 to 20 over proof_.

    A Treatise on Adulterations of Food, and Culinary Poisons Exhibiting the Fraudulent Sophistications of Bread, Beer, Wine, Spiritous Liquors, Tea, Coffee, Cream, Confectionery, Vinegar, Mustard, Pepper, Cheese, Olive Oil, Pickles, and Other Articles Employed in Domestic Economy Friedrich Christian Accum 1803

  • No experimental proof has hitherto been obtained that stimulation of the cerebral organs lying above the vaso-motor centre, and which include those possessing the function of thought, ever paralyzes this centre; but, as it is only by such paralysis that cerebral conditions can induce dilatation of blood-vessels, it must follow that no _experimental proof_ at present exists that stimulation of the brain ever does cause such dilatation -- that is, ever does become a cause of hæmorrhage.

    The Education of American Girls Anna Callender Brackett

  • The proof of this lies in the words _ex ou_ just below; not _ex ôn_ (_ouranôn_) but _ex ou_ (_politeumatos_): I can find _no proof_ of the assertion (Moulton's

    Philippian Studies Lessons in Faith and Love from St. Paul's Epistle to the Philippians 1880

  • I. i.217 (15,1) in strong proof] In chastity _of proof_, as we say in armour _of proof_.

    Notes to Shakespeare, Volume III: The Tragedies Samuel Johnson 1746


Log in or sign up to get involved in the conversation. It's quick and easy.

  • A multitude of words is no proof of a prudent mind.

    Thales (635 BC - 543 BC)

    December 8, 2006

  • Well that's all of us told, isn't it?

    October 3, 2007

  • *hangs head*

    October 3, 2007

  • So that's what holds jennarenn back... ;-)

    October 3, 2007

  • A very prudent person. :-)

    October 3, 2007

  • It's prudent to pull a number of proofs before printing an edition.

    July 8, 2008

  • Precisely.

    July 9, 2008

  • You're right, especially in large math books. Leave them wanting more for the next edition.

    July 9, 2008

  • It's often useful to assume that people reading your message do not believe what you're telling them. It may not be the case for all of them but it's likely that a good proportion are skeptical. Offer proof wherever you can.

    '15 words that will make you money'

    July 23, 2009