\ ˈprüf How to pronounce proof (audio) \

Definition of proof

 (Entry 1 of 3)

1a : the cogency of evidence that compels acceptance by the mind of a truth or a fact
b : the process or an instance of establishing the validity of a statement especially by derivation from other statements in accordance with principles of reasoning
2 obsolete : experience
3 : something that induces certainty or establishes validity
4 archaic : the quality or state of having been tested or tried especially : unyielding hardness
5 : evidence operating to determine the finding or judgment of a tribunal
6a plural proofs or proof : a copy (as of typeset text) made for examination or correction
b : a test impression of an engraving, etching, or lithograph
c : a coin that is struck from a highly polished die on a polished planchet, is not intended for circulation, and sometimes differs in metallic content from coins of identical design struck for circulation
d : a test photographic print made from a negative
7 : a test applied to articles or substances to determine whether they are of standard or satisfactory quality
8a : the minimum alcoholic strength of proof spirit
b : strength with reference to the standard for proof spirit specifically : alcoholic strength indicated by a number that is twice the percent by volume of alcohol present whiskey of 90 proof is 45 percent alcohol



Definition of proof (Entry 2 of 3)

1 : able to resist or repel boots that were … proof against cold and wet— Robertson Davies often used in combination windproof
2 : used in proving or testing or as a standard of comparison
3 : of standard strength or quality or alcoholic content


proofed; proofing; proofs

Definition of proof (Entry 3 of 3)

transitive verb

1a : to make or take a proof or test of
b : proofread
2 : to give a resistant quality to
3 : to activate (yeast) by mixing with water and sometimes sugar or milk

Other Words from proof


proofer noun

Examples of proof in a Sentence

Noun The document was proof that her story was true. He claims that he was home when the murder was committed, but he has no proof. The proof shows that the theorem is true. Verb She proofed the story carefully.
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Recent Examples on the Web: Noun All East Bank members and employees are fully vaccinated and the proof is on file with the club, making compliance with the city’s mandate a fait accompli. Robert Channick,, 8 Jan. 2022 People have already been required for some time to show proof of full vaccination or recovery to enter restaurants and bars — as well as many nonessential shops, theaters and cinemas. Fox News, 8 Jan. 2022 Two new proof-of-concept studies published today in the journal Current Biology are among the first to show that tiny fragments of DNA in the air can be used to detect different species. Corryn Wetzel, Smithsonian Magazine, 6 Jan. 2022 The CaT Pin was designed as a proof-of-concept for future wearables, Dr. Heiss says. Benoit Morenne, WSJ, 6 Jan. 2022 The proof is in our tackle boxes, gear bags and fishing vests. Paul A. Smith, Milwaukee Journal Sentinel, 2 Jan. 2022 The proof is in numerous reports of property damage, some injuries, and fatalities in other states in the aftermath of the party. Carol Robinson |, al, 31 Dec. 2021 Social proof is a force that should be wielded and can boost your brand tremendously. Yec, Forbes, 27 Dec. 2021 The proof is in the Google trend results: Adam Sandler beat out Harry Styles, Lizzo, and Britney Spears to be the top search for celebrity style. Liana Satenstein, Vogue, 21 Dec. 2021 Recent Examples on the Web: Adjective Council members voted on party lines in August to repeal Dunn’s mask mandate for schools, using its veto-proof Republican majority. Leia Larsen, The Salt Lake Tribune, 7 Jan. 2022 Maserati Mike, who wore a bow tie and what appeared to be a bullet-proof vest, carried a bullhorn and a long rifle. Bill Glauber, Milwaukee Journal Sentinel, 18 Nov. 2021 Regardless, there is expected to be a veto-proof majority of 34 lawmakers including support from the Speaker of the Council. Kelly Mena, CNN, 8 Dec. 2021 Republicans control far more state legislatures in charge of redistricting than Democrats, leaving Maryland as one of few where Democrats have a veto-proof majority in the State House. Washington Post, 24 Nov. 2021 In spite of having a veto-proof majority of 34 out of 51 City Council members and the public advocate as co-sponsors, the legislation has not moved forward until now partly because of concerns about its legality. New York Times, 23 Nov. 2021 The Petersens are not alone in their desire for a disaster-proof home. New York Times, 12 Nov. 2021 As for the technologies that will future-proof employees in the job market, machine learning and artificial intelligence (AI) were the first choice (66%), followed by cloud-native development (49%) and blockchain (46%). Bryan Robinson, Forbes, 2 Nov. 2021 Fixing the situation is a lot harder than providing tamper-proof bottles, of course, as the massive platform Facebook has built includes the worst of humanity, as well as those eager to exploit its weaknesses. Steven Levy, Wired, 25 Oct. 2021 Recent Examples on the Web: Verb In other words, resolutions that will pandemic-proof us as much as possible. Dr. Sanjay Gupta, CNN, 29 Dec. 2021 To baby-proof the drawers, try adhesive magnetic locks, tension rods, or safety strap locks. Washington Post, 22 Nov. 2021 While Budish’s administration has been fraught with controversy and a revolving door of high-level staffers, that’s actually proof that the charter system is working, said Councilwoman Sunny Simon. Courtney Astolfi, cleveland, 21 Nov. 2021 Do invest in a good copy editor to proof your work and hire a graphic designer for cover art and content images, at a minimum — quality matters. Laura Cuttill, Forbes, 2 Mar. 2021 Uncertainty can be a real danger to a business and having effective strategies in place to future-proof a business is crucial. David Ewing, Fortune, 13 Dec. 2021 The eight yes votes are enough to veto-proof the measure, but Breed doesn’t intend to spend all the money for the program this fiscal year, according to Safaí, who is partnering with her on the proposal to spend a smaller amount. Mallory Moench, San Francisco Chronicle, 30 Nov. 2021 Rob Wilcox, the federal legal director for Everytown for Gun Safety, a gun violence prevention organization, said that’s proof the background check system works. Marlene Lenthang, ABC News, 29 Oct. 2021 As is always the case in disruptive sectors, the organizations that embrace modern designs and work to future-proof their businesses will be rewarded. Rajiv Khemani, Forbes, 24 June 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'proof.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of proof


13th century, in the meaning defined at sense 1a


1583, in the meaning defined at sense 1


circa 1699, in the meaning defined at sense 1a

History and Etymology for proof


Middle English prof, prove, alteration of preve, from Anglo-French preove, from Late Latin proba, from Latin probare to prove — more at prove

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Time Traveler for proof

Time Traveler

The first known use of proof was in the 13th century

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Dictionary Entries Near proof



proof before letter

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Statistics for proof

Last Updated

10 Jan 2022

Cite this Entry

“Proof.” Dictionary, Merriam-Webster, Accessed 18 Jan. 2022.

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More Definitions for proof



English Language Learners Definition of proof

 (Entry 1 of 3)

: something which shows that something else is true or correct
: an act or process of showing that something is true
: a test which shows that a calculation is correct



English Language Learners Definition of proof (Entry 2 of 3)

: designed or made to prevent or protect against something harmful



English Language Learners Definition of proof (Entry 3 of 3)


\ ˈprüf How to pronounce proof (audio) \

Kids Definition of proof

 (Entry 1 of 2)

1 : evidence of truth or correctness "… Is there any clear proof … or is it mere hearsay?"— Robert Lawson, Rabbit Hill
2 : a printing (as from type) prepared for study and correction
3 : a test print made from a photographic negative
4 : test entry 1 sense 2 Let's put her theory to the proof.



Kids Definition of proof (Entry 2 of 2)

: able to keep out something that could be harmful The seal on the bottle is proof against tampering.
Hint: The adjective proof is usually used in compounds. waterproof



Legal Definition of proof

1 : the effect of evidence sufficient to persuade a reasonable person that a particular fact exists — see also evidence
2 : the establishment or persuasion by evidence that a particular fact exists — see also burden of proof
3 : something (as evidence) that proves or tends to prove the existence of a particular fact — see also clear and convincing, preponderance of the evidence, reasonable doubt, standard of proof — compare allegation, argument

History and Etymology for proof

alteration of Middle English preove, from Old French preuve, from Late Latin proba, from Latin probare to prove

More from Merriam-Webster on proof

Nglish: Translation of proof for Spanish Speakers

Britannica English: Translation of proof for Arabic Speakers Encyclopedia article about proof


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