1
a
: 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
6
a
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
8
a
: 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
1
: able to resist or repel
boots that were … proof against cold and wet—
Robertson Davies
—often used in combinationRobertson Davieswindproof
2
: used in proving or testing or as a standard of comparison
3
: of standard strength or quality or alcoholic content
proofed; proofing; proofs
1
a
: to make or take a proof or test of
b
2
: to give a resistant quality to
3
: to activate (yeast) by mixing with water and sometimes sugar or milk
proofer
noun
Synonyms
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
Thomas Elias, The Mercury News, 8 Nov. 2024
The lawsuit cited the 2020 presidential election, which resulted in the Jan. 6, 2021, attack on theU.S. Capitol, where supporters of Donald Trump sought to stop the certification of Joe Biden as president, alleging without proof the election was stolen.
—Tresa Baldas, Detroit Free Press, 6 Nov. 2024
Ted Johnson, Deadline, 3 Nov. 2024
The goal is to reach Stage 2, where proof systems become fully trustless and security councils intervene only for provable bugs.
—Andrey Sergeenkov, Forbes, 17 Oct. 2024
Jenn Harris, Los Angeles Times, 25 Oct. 2024
By encouraging and enabling others to grow, take risks and fuel innovation, business leaders are not only driving greater engagement and performance, but also future proofing their organization for years to come.
—Fortune Editors, Fortune, 2 Oct. 2024
See all Example Sentences for proof 
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Noun
Schwarzenegger is proof that the Republican label doesn’t have to be poison in California.
—Thomas Elias, The Mercury News, 8 Nov. 2024
The lawsuit cited the 2020 presidential election, which resulted in the Jan. 6, 2021, attack on theU.S. Capitol, where supporters of Donald Trump sought to stop the certification of Joe Biden as president, alleging without proof the election was stolen.
—Tresa Baldas, Detroit Free Press, 6 Nov. 2024
Adjective
Trump’s attacks on the media are routine, but at the Lititz, PA event, Trump was talking about the bullet proof glass that now surrounds him at outdoor events since the assassination attempt on his life in July.
—Ted Johnson, Deadline, 3 Nov. 2024
The goal is to reach Stage 2, where proof systems become fully trustless and security councils intervene only for provable bugs.
—Andrey Sergeenkov, Forbes, 17 Oct. 2024
Verb
Here, bagels are treated like artisanal breads that are proofed, boiled and baked into something worthy of a sit-down meal.
—Jenn Harris, Los Angeles Times, 25 Oct. 2024
By encouraging and enabling others to grow, take risks and fuel innovation, business leaders are not only driving greater engagement and performance, but also future proofing their organization for years to come.
—Fortune Editors, Fortune, 2 Oct. 2024
See all Example Sentences for proof
Articles Related to proof
Dictionary Entries Near proof
Cite this Entry
“Proof.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/proof. Accessed 26 Nov. 2024.
Copy CitationKids Definition
proof
1 of 3 noun1
a
: evidence of truth or correctness
gave proof of her statement
b
: 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
2
a
: a copy (as of something set in type) taken for study and correction
b
: 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 compoundswaterproof
proof
3 of 3 verb
: to activate (yeast) by mixing with water
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