\ ˈprüf \

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

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Other Words from proof


proofer noun

Examples of proof in a Sentence


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.


She proofed the story carefully.
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Recent Examples on the Web: Noun

The proof is not only on the men’s Fall 2019 runways, but in the outfits worn by guests outside. Madeline Fass, Vogue, "5 Menswear Style Hacks Every Woman Should Know," 14 Jan. 2019 An athlete works toward a goal and is rewarded with concrete proof of his effort. Brendan Tapley, Woman's Day, "10 Things Men Wish Women Knew About the Way They Think," 6 Nov. 2018 Harry’s dedication to humanitarian causes, particularly injured servicemen and women, also shone throughout the tour, with the proof of his hard work surrounding him and Meghan every day. Omid Scobie, Harper's BAZAAR, "What It's Like to Go on Tour with Prince Harry and Duchess Meghan," 3 Nov. 2018 Joann Fabric and Crafts: Its prime match pledge applies to identical, in-stock items advertised withing the past 7 days and includes ads for competitors with proof of lower price via original/current ad or print-out of online price. Doreen Christensen,, "Forget Prime Day. These 10 stores will price-match Amazon every day of the week," 9 July 2018 El Fenix: Active duty and retired military members get 15 percent off for Independence Day with proof of service. Kelly Tyko, USA TODAY, "Oorah! Where active military, vets can save on Independence Day," 1 July 2018 El Fenix: Active duty and retired military members get 15 percent off for Independence Day with proof of service. Kelly Tyko, ajc, "Oorah! Where active military, vets can save on Independence Day," 1 July 2018 However, Glencoe residents with beach tokens can go to Winnetka’s Maple Hill and Elder beaches on the holiday or pay the $5 residency rate with proof of residency. Daniel I. Dorfman,, "How to celebrate the Fourth of July in Glencoe," 26 June 2018 Jack White's Third Man Records announced on Wednesday (June 20) that anyone visiting its Nashville and Detroit stores with proof of their $50 donation to RAICES will score free, limited-edition vinyl swag from the label. Gil Kaufman, Billboard, "Common, Jack Antonoff, Decemberists, Oh Boy Records & More Help Raise Funds For Immigrant Support Groups," 22 June 2018

Recent Examples on the Web: Adjective

For Fall 2019, Abloh may have only nodded to the harness with giant leather sashes and a bullet-proof vest-like piece, but the vibe still looms large in his aesthetic. Brooke Bobb, Vogue, "Virgil Abloh, Michael Jackson, and the History of the Male Fashion Harness," 17 Jan. 2019 Use dry, heat-proof tongs or wooden chopsticks to transfer dredged chicken pieces to hot oil, taking care not to splash and making sure pot is not overcrowded. Gabriella Gershenson, WSJ, "The Greatest New Year’s Menus on the Planet (at Least We Think So)," 26 Dec. 2018 In Orange, the county pledged $25,000 in matching funds to earn a $200,000 FWC grant, which the solid-waste division used to buy 918 lock-top, bear-proof garbage containers. Stephen Hudak,, "Apopka to consider bear ordinance, bear-resistant trash cans," 26 June 2018 Transfer to a clean, heat-proof container and let set in the refrigerator overnight. Kelsey Kloss, ELLE Decor, "3 Father's Day Cupcakes To Match His Favorite Drink," 14 June 2016 The direct-to-consumer company designs carry-ons and checked bags that prioritize functionality over trends: sturdy handles molded to your grip, a scratch-proof finish, and durable zippers. Lale Arikoglu, Condé Nast Traveler, "Why Everyone Wants an Away Suitcase," 26 Nov. 2018 And Democrats are unlikely to have a filibuster-proof Senate supermajority any time soon. David Roberts, Vox, "After the midterms, US climate politics are even more polarized. Here’s how Dems can move forward.," 12 Nov. 2018 Web-slinging boils down to a limited simple set of buttons, and these, combined with Insomniac's graceful inclusion of idiot-proof timing windows, make the act of sailing across Manhattan feel peerless in gaming. Sam Machkovech, Ars Technica, "Spider-Man PS4 review: Does whatever a spider can—and then some," 4 Sep. 2018 Of course the new town cannot recreate the old, but in looking to a 21st century, earthquake-proof Amatrice, the Mayor is just hoping to somehow save the town’s identity. Amy Kellogg, Fox News, "Central Italy battling effects of earthquakes and bureaucracy as it struggles to rebuild," 24 Aug. 2018

Recent Examples on the Web: Verb

And, as the weather gets colder, there is so much more to cover: how to winter-proof your car, how to drive cautiously in ice and snow, and how to trouble-shoot cold-weather problems. Jasmin Radoncic, Good Housekeeping, "How to Use Jumper Cables and Jump Start a Car the Right Way," 5 Dec. 2018 This means that there isn't proof positive these structures are there. John Wenz, Popular Mechanics, "Menacing Ice Spikes on Europa Could Endanger Future Landers," 8 Oct. 2018 Wet n Wild Photo Focus Foundation Wet n Wild tested this formula under seven different lighting conditions with top smartphone models to essentially selfie-proof their product. Allure, "The 17 Best Drugstore Foundations for All Your Coverage Needs," 6 Sep. 2018 Theater people have the best advice on sweat-proofing makeup Who among us hasn’t pirouetted all night (literally or figuratively) and felt their foundation start to slide off? Jamie Beckman, Allure, "Backstage Beauty Secrets From the Cast and Crew of Hamilton and Sleep No More," 13 Aug. 2018 Even tiny cracks in the weather-proofing around cables can allow water molecules to embed in the strands and attenuate the signal. Rob Goodier, Popular Mechanics, "How Climate Change Could Break the Internet," 19 July 2018 Check out how to get rid of as much dust in your home as possible, along with how to pollen-proof your place. Korin Miller, SELF, "What’s an Asthma Exacerbation? (Because It Sounds Really Scary.)," 11 July 2018 Never has the drama of a proofing drawer felt more alive and essential. Margaret Lyons, New York Times, "How Much Watching Time Do You Have This Weekend?," 21 June 2018 The two men proofed each other’s papers, talked about assignments, took turns at an improvised desk in the cell with a toilet seat as the chair. Nick Anderson, Washington Post, "‘Could I make it in college?’: His journey to a bachelor’s degree started behind bars," 24 May 2018

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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Statistics for proof

Last Updated

5 Feb 2019

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Time Traveler for proof

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

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More Definitions for proof



English Language Learners Definition of proof

 (Entry 1 of 2)

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



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

formal : designed or made to prevent or protect against something harmful


\ ˈprüf \

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

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More from Merriam-Webster on proof

Rhyming Dictionary: Words that rhyme with proof

Thesaurus: All synonyms and antonyms for proof

Spanish Central: Translation of proof

Nglish: Translation of proof for Spanish Speakers

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

Comments on proof

What made you want to look up proof? Please tell us where you read or heard it (including the quote, if possible).


esteemed in general opinion

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