proof

noun

Save Word

\ 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

proof

adjective

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

proof

verb

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 Synonyms & Antonyms More Example Sentences Learn More About proof

Keep scrolling for more

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.

Recent Examples on the Web: Noun Beginning August 30, the chain is giving anyone with vaccination proof two free doughnuts every day until September 5. — Jordan Valinsky, CNN, 25 Aug. 2021 Following that announcement, California Governor Gavin Newsom announced all school teachers and staff in the state would be required to show proof of vaccination or a take regular COVID-19 tests. — Caitlin O'kane, CBS News, 24 Aug. 2021 The online application for the grants requires proof of residency and documentation of eligible expenses. — From Usa Today Network And Wire Reports, USA TODAY, 24 Aug. 2021 Check them out at a local bookstore; just bring your mask and proof of vaccination. — Los Angeles Times, 24 Aug. 2021 They’ll be required to wear masks indoors but will not have to show proof of vaccination or a negative COVID test to gain entry. — Childs Walker, baltimoresun.com, 24 Aug. 2021 Fans entering Tiger Stadium this fall for football games will need to provide proof of vaccination or a negative COVID PCR test, LSU said in a release Tuesday. — Mark Heim | Mheim@al.com, al, 24 Aug. 2021 That may mean sitting in pods of one to four people as per the guidelines for Portland Baroque Orchestra concertgoers or showing proof of vaccination or a negative COVID test (that includes the outdoor performances listed below). — oregonlive, 24 Aug. 2021 Penrose pieced together clues that suggested a conjecture—an informed guess, not an airtight proof—that general relativity would never make that prediction. — Brendan Z. Foster, Scientific American, 23 Aug. 2021 Recent Examples on the Web: Adjective Removable wallpaper with a peel-and-stick application is a fool-proof way to bring a plain space to life. — Shivani Vyas, Better Homes & Gardens, 23 July 2021 There is one fool-proof way to assess an agency in a pitch—and that is, to assess its leadership stability. — Avi Dan, Forbes, 10 June 2021 Michigan Republicans this week proposed changes to state voting laws and have come up with a veto-proof way to circumvent Democrat Gov. Gretchen Whitmer, according to reports. — Fox News, 24 Feb. 2021 Hang easy-to-read, weather-proof signs within a mile of your house with heavy-duty tape, or use the existing nails on wood poles (where allowed). — Samantha S. Thorpe, Better Homes & Gardens, 29 July 2021 Take 30% off the Power Play Foundation, a sweat-proof liquid foundation that makes your skin look like skin but better by blurting out imperfections. — Jennifer Ford, Forbes, 21 June 2021 Shatter-proof windows at the Pico-Robertson synagogue prevented the concrete from breaking the glass, and the concrete bounced back onto the sidewalk. — Matt Hamilton, Los Angeles Times, 29 May 2021 Johnson helped organize a string of protests across Britain last summer and had been recorded speaking to crowds in the streets while wearing a stab-proof vest and camouflage print trousers. — Washington Post, 23 May 2021 Crucially, their negotiations brought 11 GOP senators on board a plan that could summon a filibuster-proof majority to pass significant legislation on a top priority for Biden and the Democrats. — Ronald J. Hansen, The Arizona Republic, 26 June 2021 Recent Examples on the Web: Verb Cover the dough and set aside in a warm area to proof for 1 to 2 hours, or until doubled in volume. — Time, 12 Aug. 2021 This approach assumes that humans will often make mistakes and that the most effective road to patient safety is to error-proof the system. — Stephan Landsman, STAT, 6 Aug. 2021 American gas-station owners are facing a tough decision over whether to invest in electric-vehicle charging stations, a costly bet that currently makes little financial sense but might help future-proof their businesses. — Jennifer Hiller, WSJ, 10 Aug. 2021 The problem, Professor Travers said, is that London’s weather is usually so moderate and predictable that no single weather episode, however damaging, is likely to galvanize politicians into taking major action to climate-proof the city. — Mark Landler, New York Times, 2 Aug. 2021 In addition, consider upgrading technology to incorporate human-assisting analytics, AI and machine learning tools that not only meet needs today but will help future-proof your business for what is to come. — Tom Goodmanson, Forbes, 17 May 2021 Those who want to future-proof their home theaters will want to check out the Samsung Q900TS QLED 8K Smart TV. — Andrew Myrick, Forbes, 28 May 2021 The message is becoming clearer: To future-proof your PC, Microsoft is now requiring it to maintain a minimum level of security. — Mark Hachman, PCWorld, 28 June 2021 Haack, who also shares daughter Taylor Reese, 10, and son Brayden James, 5, with ex-husband and Flip and Flop costar Tarek El Moussa, then shares that baby Hudson is the first child she's had to baby proof her home for. — Georgia Slater, PEOPLE.com, 17 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.

Keep scrolling for more

Learn More About proof

Dictionary Entries Near proof

prooemium

proof

proof before letter

Statistics for proof

Last Updated

26 Aug 2021

Cite this Entry

“Proof.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/proof. Accessed 29 Aug. 2021.

Style: MLA

MLA

Chicago

APA

Merriam-Webster Check Mark Icon

Seen & Heard

People are talking about

Keep scrolling for more

More Definitions for proof

proof

noun

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

proof

adjective

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

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

See the full definition for proof in the English Language Learners Dictionary

proof

noun

\ 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.

proof

adjective

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

proof

noun

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 sense 1a