proof

1 of 3

noun

ˈprüf

Synonyms of proof next

: the cogency of evidence that compels acceptance by the mind of a truth or a fact

: the process or an instance of establishing the validity of a statement especially by derivation from other statements in accordance with principles of reasoning

obsolete : experience

: something that induces certainty or establishes validity

archaic : the quality or state of having been tested or tried

especially : unyielding hardness

: evidence operating to determine the finding or judgment of a tribunal

plural proofs or proof : a copy (as of typeset text) made for examination or correction

: a test impression of an engraving, etching, or lithograph

: 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

: a test photographic print made from a negative

: a test applied to articles or substances to determine whether they are of standard or satisfactory quality

: the minimum alcoholic strength of proof spirit

: 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

proof

2 of 3

adjective

: able to resist or repel

boots that were … proof against cold and wet—

Robertson Davies

—often used in combination

windproof

: used in proving or testing or as a standard of comparison

: of standard strength or quality or alcoholic content

proof

3 of 3

verb

proofed; proofing; proofs

transitive verb

: to make or take a proof or test of

: proofread

: to give a resistant quality to

: to activate (yeast) by mixing with water and sometimes sugar or milk

proofer noun

Example Sentences

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.

Recent Examples on the Web

Noun

As was reflected by Deputy District Attorney Ariel Anson’s closing arguments, a notable change compared to the first trial was that prosecutors told jurors directly that Masterson drugged the three women who accused him of rape, though there wasn’t any proof of that allegation. —

Ethan Millman, Rolling Stone, 16 May 2023 Applicants must submit documents including their identification and proof of household income levels. —

Laura Groch, San Diego Union-Tribune, 14 May 2023 Residents of the same household as listed above (driver's license required for proof of residency). —

Tanya Wildt, Detroit Free Press, 13 May 2023 One of its members claims to have proof that dinosaurs lived together with humans and that a sample of dinosaurs was saved from a global flood on Noah’s Ark. Would any of his colleagues in this group publicly disagree? —

Heslley Machado Silva, Scientific American, 12 May 2023 Could a conservative state demand proof that those products weren't made by immigrants in the country illegally? —

John Fritze, USA TODAY, 11 May 2023 After Nobals completed the upset — winning the $500,000 Grade 2 stakes race at Churchill Downs by 3/4 of a length over Motorious — Rivelli produced proof of his confidence. —

Alexis Cubit, The Courier-Journal, 6 May 2023 The company’s patents cite Mr. Saltman’s early reports on punch-card vulnerabilities as proof that Dominion’s voting technology had overcome those flaws. —

Sam Roberts, BostonGlobe.com, 6 May 2023 But some of his allies in conservative media have — without offering proof — blamed Fox for trying to tarnish the reputation of its former star host, saying the network is looking to hamstring his career prospects. —

Benjamin Mullin, New York Times, 5 May 2023

Adjective

One user claimed the High-frequency Active Auroral Research Program is proof weather-manipulation inventions exist, but USA TODAY has previously debunked that claim. —

Eleanor Mccrary, USA TODAY, 10 Nov. 2022 According to the official tasting notes, this 86.5 proof whiskey has cinnamon, nutmeg, sweet vanilla, cinnamon, cloves, and plums on the palate, followed by a warm oak finish. —

Jonah Flicker, Robb Report, 9 May 2023 The place is immaculate, and the only items on the counter are the bare essentials: a brick of toilet paper and an unopened bottle of 100 proof bourbon. —

Globe Staff, BostonGlobe.com, 24 Feb. 2023 But our walk-in closet was hardwood, which was proof enough for me. —

Laura Johnston, cleveland, 10 Sep. 2022 Use a high-quality and high-proof bourbon as the spirit. —

Maggie Menderski, The Courier-Journal, 10 Apr. 2023 Keep your laptop close, accessible, and, perhaps most importantly, dry thanks to this weather-proof shoulder bag. —

Austa Somvichian-clausen, Travel + Leisure, 7 Apr. 2023 The couch’s eucalyptus wood base and plush beige zippered cushions provides an elegance without sacrificing weather-proof durability. —

Gabriela Izquierdo, Better Homes & Gardens, 7 Apr. 2023 Our Top Picks 1 2 3 4 5 Best 7/8 Option Athleta Elation Train 7/8 Leggings Read more Best Overall Leggings Nike Go Firm-Support High-Waisted 7/8 Leggings Pros Squat-proof Multiple pockets Drawcord waist Cons Size Range: 00 -22 These Firm-Support leggings offer compression with a capital C. —

Hannah Oh, seventeen.com, 6 Apr. 2023

Verb

This may include headache-proofing your home or modifying your diet and lifestyle. —

Mikayla Morell, Health, 2 Apr. 2023 Popping open a stack of dough proofing containers in their walk-in refrigerator, Mr. Federighi revealed an overlapping stack of pizza skins — what pizzamakers call dough that’s been stretched but not yet topped — that were dry to the touch, with the texture of cured leather. —

J. Kenji López-alt, New York Times, 17 Mar. 2023 While yeast is proofing, whisk together the butter, egg yolks, and vanilla extract. —

Emanuella Grinberg, CNN, 20 Feb. 2023 For instance, capoeira, a martial art that originated in Brazil among enslaved Africans, is proof our creative ingenuity and autonomous expression can transcend us even when we’ve been stripped of our license to speak and deprived of our identities and cultures. —

Marjua Estevez, refinery29.com, 24 Feb. 2023 Future-proofing businesses has been high on strategic agendas for many organizations in their efforts to keep pace with fast-evolving digital transformation efforts. —

Michel André, Forbes, 21 Feb. 2023 The pyrotechnics ignited the sound-proofing foam near the stage, and the flames licked their way up the wall. —

Amanda Milkovits, BostonGlobe.com, 19 Feb. 2023 Tick-proof your gear. —

Lauren Krouse, Health.com, 18 May 2021 This waterproof rain jacket is proof your rainy day fit can — and should — look runway-ready chic. —

Marissa Miller, Travel + Leisure, 13 Mar. 2023 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'proof.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

Noun

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

First Known Use

Noun

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

Adjective

1583, in the meaning defined at sense 1

Verb

circa 1699, in the meaning defined at sense 1a

Time Traveler

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

See more words from the same century

Cite this Entry

Style

“Proof.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/proof. Accessed 6 Jun. 2023.

Copy Citation

Kids Definition

proof

1 of 3 noun

ˈprüf

: evidence of truth or correctness

gave proof of her statement

: an act or process of showing or finding out that something is true especially by reasoning or by experiment

a proof that the theorem is true

put a theory to the proof

: a copy (as of something set in type) taken for study and correction

: a test print made from a photographic negative

proof

2 of 3 adjective

: designed or made to prevent or keep out something that could be harmful

this lock is proof against tampering

—often used in compounds

waterproof

proof

3 of 3 verb

: to activate (yeast) by mixing with water

Legal Definition

proof

noun

: the effect of evidence sufficient to persuade a reasonable person that a particular fact exists see also evidence

: the establishment or persuasion by evidence that a particular fact exists see also burden of proof

: 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

: probate sense 1a

Etymology

Noun

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