proof
Pluralproofs (some meanings)
Pluralproofs (some meanings)
Formsproofs, proofing, proofed
- 1Facts, information or a paper that show something is true.
Like a receipt that shows you really paid for something.
The police need proof before they can arrest anyone.
Her photo was proof that she had really met the singer.
UsageSay proof of something or proof that it is true. The verb is prove.
Similartestament
Oppositedisproof, refutation
Note
- 2A set of steps that shows, one by one, why a math statement must be true.
Like climbing a ladder: each step rests on the one below it until you reach the top.
Our teacher showed us a simple proof that the angles of a triangle add up to 180 degrees.
He wrote out the proof step by step on the board.
UsageSay a proof of a fact or a proof that it is true.
Similardemonstration, derivation
Oppositedisproof
Note
- 3Strong enough to resist something and not be harmed by it.
The new safe is proof against fire.
Her good mood was proof against all his complaints.
UsageSay proof against something. It also ends words like waterproof.
Similarresistant, impervious, immune, invulnerable
Oppositevulnerable, susceptible
Note
- 4
- 5A test or check to find out whether something is true, correct, strong, or reliable.
The first cold winter will be the real proof of our new heater.
Check your subtraction with a quick proof: add your answer to the smaller number and see if you get the bigger one.
UsageFound in phrases like put something to the proof.
Note
- 6To treat something so that water or other things cannot easily get in or harm it.
You should proof your boots before walking in the snow.
Dad proofed the tent with a special spray last summer.
UsageSay you proof something against rain.
Similarwaterproof, seal, treat, weatherproof
- 7
Less common meanings
- 8A number that tells you how strong an alcoholic drink is.
Check the proof on the bottle before you pour a strong drink.
Whiskey with a high proof can burn your throat.
UsageSay a drink has a high proof when it is very strong.
Similarstrength
Note
- 9In baking, to leave bread dough to rise before baking, or to check that yeast is still alive.
Proof the dough for about an hour before baking.
Let the dough proof in a warm place until it doubles in size.
UsageYou can say proof the dough or let the dough proof.
Note
- 10Having a certain level of alcohol, shown by a number.
The vodka in the cabinet is 80 proof.
Drinks that are 100 proof are very strong.
UsageSay a drink is 80 proof, or an 80-proof drink.
- 11Hardness or strength that nothing can break through or press into.
Similarstrength, resistance, toughness, impenetrability, hardness
Oppositeweakness, vulnerability
Note
- 12Strong armor that people believed weapons could not cut or break through.
Till that Bellona's bridegroom, lapped in proof
c. 1606, William Shakespeare, “The Tragedie of Macbeth”Here, proof means very strong armor.Similararmor
Note
- 13Knowledge of something that you gained by living through it yourself.
But the chaste damzell, that had never priefe / Of such malengine and fine forgerye, / Did easely beleeve her strong extremitye.
1590, Edmund Spenser, The Faerie QueeneHere, priefe means experience, knowing something firsthand.Note
- 14A strong and steady mind that nothing can shake.
Note
- 15A specially made coin with a very shiny, mirror-like surface, sold to collectors instead of being spent.
- 16Made or used for testing whether something works or is strong enough.
- 17To test a gun by firing it with a much stronger charge than normal, to make sure it cannot burst.
Showing meanings only.
Practice
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Origin
From Latin "probo," meaning "to prove." It came into English through Old French and Late Latin.
Checked 6 Nov 2026 · 3 facts
- Proof ultimately derives from Latin probō through proba. en.wiktionary.org
- Latin probō means to prove. en.wiktionary.org
- Proof entered English through Old French, with a Late Latin antecedent. en.wiktionary.org