1

proof

noun \ ˈprüf \
Updated on: 24 Nov 2017

Definition of proof

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

Examples of proof in a Sentence

  1. The document was proof that her story was true.

  2. He claims that he was home when the murder was committed, but he has no proof.

  3. The proof shows that the theorem is true.

Recent Examples of proof from the Web

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


2

proof

adjective

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

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

Other Alcoholic Beverage Terms


3

proof

verb

Definition of proof

transitive verb
1 a : 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

proofer

noun

Examples of proof in a Sentence

  1. She proofed the story carefully.

Recent Examples of proof from the Web

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



PROOF Defined for English Language Learners

proof

noun

Definition of proof for English Language Learners

  • : 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

Definition of proof for English Language Learners

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


PROOF Defined for Kids

1

proof

noun \ ˈprüf \

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.

2

proof

adjective

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

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 1a

Origin and Etymology of proof

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



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