Proof is the evidence that shows something is true or valid. When you show the logical steps that take you from your hypothesis that the world is round to the conclusion that it is, you're formulating a proof.

Photographic prints that haven't been touched up are also called proofs, and that’s also what you call the first copy of a printed text, before it's checked for errors and corrected. When you check a text for errors, you're proofing. If your poker strategy is foolproof, even somebody who knows nothing about poker — a poker fool, that is — can’t get it wrong. Proof is a word you’ll see on bottles of alcohol, too: 90-proof rum means it's 45% alcohol.

Primary Meanings of proof

any factual evidence that helps to establish the truth of something
(printing) an impression made to check for errors
read for errors
make resistant (to harm)
(used in combination or as a suffix) able to withstand
a measure of alcoholic strength expressed as an integer twice the percentage of alcohol present (by volume)
knead to reach proper lightness
Full Definitions of proof

n any factual evidence that helps to establish the truth of something

“if you have any proof for what you say, now is the time to produce it”
cogent evidence
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check, confirmation, substantiation, verification
additional proof that something that was believed (some fact or hypothesis or theory) is correct
establishment, validation
the cognitive process of establishing a valid proof
bed check
a check that everyone is in bed by the time they should be
an instance of confirming something by considering information from several sources
odd-even check, parity check, redundancy check
a system of checking for errors in computer functioning
a digit representing the sum of the digits in an instance of digital data; used to check whether errors have occurred in transmission or storage
Type of:
evidence, grounds
your basis for belief or disbelief; knowledge on which to base belief

n a formal series of statements showing that if one thing is true something else necessarily follows from it

mathematical proof
proof of a mathematical theorem
logical proof
proof of a logical theorem
demonstration, monstrance
proof by a process of argument or a series of proposition proving an asserted conclusion
Type of:
argument, statement
a fact or assertion offered as evidence that something is true

n the act of validating; finding or testing the truth of something

substantiation, validation
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authentication, certification
validating the authenticity of something or someone
documentation, support
documentary validation
monetisation, monetization
establishing something (e.g. gold or silver) as the legal tender of a country
the act of proving that an instrument purporting to be a will was signed and executed in accord with legal requirements
Type of:
determination, finding
the act of determining the properties of something, usually by research or calculation

n (printing) an impression made to check for errors

test copy, trial impression
galley proof
a proof taken before the type is broken up to print pages
foundry proof
a proof taken from a form before duplicate plates are made
Type of:
impression, printing
all the copies of a work printed at one time

n a trial photographic print from a negative

Type of:
photographic print, print
a printed picture produced from a photographic negative

v read for errors

Type of:
ascertain, assure, check, control, ensure, insure, see, see to it
be careful or certain to do something; make certain of something

v make or take a proof of, such as a photographic negative, an etching, or typeset

Type of:
create, make, produce
create or manufacture a man-made product

v make resistant (to harm)

proof the materials against shrinking in the dryer”
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make safe against bombings
make bulletproof
child-proof, childproof
make safe against children
foolproof, goof-proof, goofproof
proof against human misuse or error
make resistant to fire
make resistant to bad weather
Type of:
gain strength

adj (used in combination or as a suffix) able to withstand

“temptation- proof
imperviable, impervious
not admitting of passage or capable of being affected

n a measure of alcoholic strength expressed as an integer twice the percentage of alcohol present (by volume)

Type of:
amount, measure, quantity
how much there is or how many there are of something that you can quantify

v knead to reach proper lightness

proof dough”
Type of:
knead, work
make uniform

v activate by mixing with water and sometimes sugar or milk

proof yeast”
Type of:
alter, change, modify
cause to change; make different; cause a transformation

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