Proof

How to spell proof

5 letters · 1 syllable

How to pronounce proof

What does proof mean?

1. nounEvidence or an argument that establishes that something is true.
2. nounA trial impression of printed text or images, made so corrections can be marked before final printing.
3. nounA standard measure of the strength of a distilled alcoholic spirit.
4. verbTo read text carefully to find and mark errors, or to let dough rise before baking.

Proof in a sentence

• noun

  The receipt is your proof of purchase.

• noun

  The editor returned the proof covered in red corrections.

• noun

  The whisky was bottled at a high proof and burned on the way down.

• verb

  Please proof the report before it goes to the client.

• noun

  The lawyer demanded proof that the contract had been signed.

• noun

  The author reviewed the first proof before the book went to press.

Where does proof come from?

Language of origin: Latin

The word descends from the Latin verb probare, which meant 'to test, examine, or judge as good', itself built on probus, meaning 'honest, upright, of good quality'. From this came the Late Latin noun proba, 'a test or trial', which passed into Old French as preuve or prove, meaning a demonstration of truth. English borrowed it in the 1200s, and over the centuries the spelling drifted from 'preve' and 'prove' toward 'proof', settling on the double-o to mark the long vowel. The same root gives us the verb 'prove', the words 'probe' and 'probable', and even 'approve', so the family all circles around the idea of testing something to confirm it is sound. The shift from the verb spelling 'prove' to the noun spelling 'proof' is exactly the trap, since the two relatives no longer look alike.

How the word is built

• proof (from Latin probare, to test or prove); a noun and verb formed from the same root as 'prove', with the vowel preserved in the spelling