Definition of proof
1a : the cogency of evidence that compels acceptance by the mind of a truth or a factb : 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 correctionb : a test impression of an engraving, etching, or lithographc : 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 circulationd : 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 spiritb : 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
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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.
Recent Examples of proof from the Web
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The group’s increasingly urgent appeals for lone-wolf attacks is proof that such efforts are working, said Justin Siberell, the State Department’s acting coordinator for counterterrorism.
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As proof, Thielman posted a screenshot of a video to Twitter, in which Abe gives a keynote address in English at a 2014 coastal resilience symposium.
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Proof Eyewear employs eight people full-time, three part-time.
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As secretary of state in Kansas, Kris Kobach introduced the SAFE Act, which requires first-time voters to provide proof of citizenship when registering to vote.
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Leiden Observatory astronomy student and tour guide Alex Pietrow offers proof in photographs of the solar system taken with an original Game Boy Camera.
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Wilson wrote multiple letters to the Department of Education demanding proof that Morel had taken out the loans – and an explanation of how the wage garnishments were allowed without a court judgment.
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Vice President Pence is the chair of the panel and Kansas Secretary of State Kris Kobach (R), a former state GOP chairman who has long insisted without proof that there is widespread voter fraud, is the vice chair.
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The 2017 draft was further proof of the NBA’s direction.
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.
Origin and Etymology of proof
Middle English prof, prove, alteration of preve, from Anglo-French preove, from Late Latin proba, from Latin probare to prove — more at prove
Other Logic Terms
proof
Definition of proof
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
Recent Examples of proof from the Web
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Manufacturers of the cladding fought additional restrictions and testing, citing the additional cost of fire-resistant or fire-proof building materials, and government regulators ultimately didn’t act.
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Pour into a heat-proof jar and allow to cool to room temperature, uncovered.
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There are 52 Republicans in the Senate, eight members short of a filibuster-proof majority.
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Beyond the fundamental result, such experiments also point to the possibility of hack-proof communications.
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Images posted to social media appeared to show heavily armed officers in camouflage outfits and bullet-proof vests on board the plane.
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And Mr. Scott is, in any case, a nearly spoiler-proof filmmaker.
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The soft spot, the least tyrant-proof part of the government, is the U.S. Department of Justice and the larger law enforcement and regulatory apparatus of the United States government.
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At the center is a snoop-proof courtroom capable of trying six alleged co-conspirators before one judge and jury.
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.
First Known Use of proof
1583
proof
Definition of proof
transitive verb
1a : to make or take a proof or test ofb : proofread
2 : to give a resistant quality to
3 : to activate (yeast) by mixing with water and sometimes sugar or milk
proofer
nounExamples of proof in a Sentence
She proofed the story carefully.
Recent Examples of proof from the Web
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Here, proof the two are very much their own people, er, dogs.
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Lonzo Ball’s TV Foot Locker ad, a Father’s Day spoof of his old man: Proof an acorn can fall far from the tree.
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China has spent the past two months bomb-proofing its financial system for the Federal Reserve.
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Was that moony look Justin gave Emmanuel at the G7 summit in Sicily proof the Canadian prime minister is crushing on his French counterpart?
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Other options include sound-proofing walls along the route, better traffic signal timing at eight intersections, and improved interchanges between Southwest 10th Street and the three highways.
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On social media, however, many in the anarchist and antifascist camps pointed to Coulter’s cancellation as proof their use of violence as a tool works.
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Disaster-proofing your retirement by implementing these three strategies doesn’t simply help increase your chances of achieving financial success.
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.
First Known Use of proof
circa 1699
Other Printing Terms
epigraph, errata, leader, mechanical, notch, tittle, underscore, widow
PROOF Defined for English Language Learners
proof
playDefinition of proof for English Language Learners
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: something which shows that something else is true or correct
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: an act or process of showing that something is true
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mathematics : a test which shows that a calculation is correct
proof
Definition of proof for English Language Learners
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: designed or made to prevent or protect against something harmful
PROOF Defined for Kids
Definition of proof for Students
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 : 1test 2 Let's put her theory to the proof.
Definition of proof for Students
: 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
Law Dictionary
proof
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
4 : probate 1a
Origin and Etymology of proof
alteration of Middle English preove, from Old French preuve, from Late Latin proba, from Latin probare to prove
Learn More about proof
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See 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 Britannica.com: Encyclopedia article about proof
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