I've been wondering for a long time when I should use proof and when prove. They seem so awfully similar and I can't get hands on any good examples that would show the key differences. I know both of the words have to do with confirming or considering as truth of some sort.

What are the key differences between 'proof' and 'prove'? Examples would be much appreciated.

  • Proof is a noun; prove is a verb. Examples: "The mathematician proved the theorem. The theorem was first proved in a proof published in 1826." Or: "We had to do ten proofs last night for homework. The last one was very hard to prove!"
    – J.R.
    Commented Sep 25, 2013 at 10:30
  • @J.R. Proof: verb, adjective, noun, Prove: verb
    – 3ventic
    Commented Sep 25, 2013 at 10:32
  • Yes, but proof as a verb has little in common with prove as a verb. That's a different nuance of the word than what you have asked about; it is related to waterproofing and writing.
    – J.R.
    Commented Sep 25, 2013 at 10:34
  • 1
    I don't think OP even tried to check any of them in a dictionary. If he had had, he probably did not ask this question because in that case, he would already have got his answer by now.
    – Mistu4u
    Commented Sep 25, 2013 at 11:46
  • 4
    I think @Mistu4u is hinting at the fact that you probably could have done a better job of explaining what you already understood, and what you still were looking for help to understand. The question as it stands now is vague and shows no research (the community has discussed this already; you can read more here). As for me "answering without answering", I was just giving you an initial hint of an answer; I had a feeling someone else would take the time to do a more thorough job (as chrylis has admirably done).
    – J.R.
    Commented Sep 25, 2013 at 13:59

1 Answer 1


"Proof" and "prove" both come from the same word (Latin probus). Usually, "proof" is a noun that means "evidence", and "prove" is a verb that means "demonstrate". You prove that an accusation is true by showing proof.

There are a few special cases to be aware of, but they're all technical terms:

  • So-much-"proof" as an adjective can refer to the alcohol content of a drink (1 proof is 0.5% alcohol by volume). This comes from an old practice of using gunpowder to provide "proof" in the usual sense of the alcohol content.
  • Both "proof" and "prove" can be a verb meaning to let bread rise with yeast.
  • "Proof" as a noun can mean an example of a product to be produced, such as a book to be printed or a sample copy of a business card. "Proofreading", meaning to examine a sample copy for errors, comes from this meaning.
  • "Something-proof" is an adjective that means "resistant to something", such as a waterproof tent or soundproof walls.
  • A mathematical or logical proof is a specific variety of proof that proves that a conclusion is true if certain assumptions are true.

There are a number of other rare uses of "proof", but these are the ones you're likely to encounter. The word proof/prove is a very old one; it at least goes back to Roman Latin, and so it has gained some specific meanings in different fields (such as its use to measure alcohol) that are now far removed from the original processes.

  • 1
    When equating "proof" with "evidence" beware that "evidence" can mean either full demonstration of fact (in which case they're equivalent) or just partial information that indicates some conclusion but is only one part of a proof (in which case they're different). A trial, for example, can involved plenty of evidence on either side that ultimately proves nothing. Commented Aug 23, 2014 at 14:26

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