The word proof can mean:
- originally, a test assessing the validity or quality of something.
- a rigorous, compelling argument, including:
- a photograph, print or page layout presented as an example for proofreading or approval
- alcoholic proof, a measure of how much alcohol is in a beverage
- Proof, a play by David Auburn
- Proof, a film by Jocelyn Moorhouse
- a Proof coin is a coin made especially for coin collectors, usually distinguished by being struck twice (or at a higher pressure) and often with polished fields and frosted devices.