plural proofs
1
: something which shows that something else is true or correct
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 photograph is proof positive [=definite proof] that the accident happened the way he described.
I'm living proof that success is possible. [=my success shows that other people can succeed too]
—often + ofThe evidence gave proof of her statement. [=the evidence proved her statement]
Do you have any proof of identity?
Keep the receipt as proof of purchase. [=evidence showing/proving that you bought something]
2
a
: an act or process of showing that something is true
The burden of proof [=the need to show that something is true] is on the prosecuting lawyer of the case.
b
mathematics
: a test which shows that a calculation is correct
The proof shows that the theorem is true.
mathematical proofs
3
technical
: a copy of something that is going to be printed which is examined and used to make corrections before the final printing is done
—usually plural
He edited the proofs of the manuscript.
4
: a measurement of how much alcohol is in an alcoholic drink
The whiskey is 80 proof.
formal
: designed or made to prevent or protect against something harmful
The seal of the bottle is proof against tampering. [=the seal prevents tampering]
—usually used in combinationwaterproof
bulletproof
Cite this Entry
“Proof.” Merriam-Webster.com Simple Definition, Merriam-Webster, https://www.merriam-webster.com/simple/proof. Accessed 14 Apr. 2026.
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