Proof n.
 1. Any effort, process, or operation designed to establish or discover a fact or truth; an act of testing; a test; a trial.
 For whatsoever mother wit or art
 Could work, he put in proof.   --Spenser.
    You shall have many proofs to show your skill.   --Ford.
    Formerly, a very rude mode of ascertaining the strength of spirits was practiced, called the proof.   --Ure.
 2. That degree of evidence which convinces the mind of any truth or fact, and produces belief; a test by facts or arguments that induce, or tend to induce, certainty of the judgment; conclusive evidence; demonstration.
    I'll have some proof.   --Shak.
    It is no proof of a man's understanding to be able to confirm whatever he pleases.   --Emerson.
 Note: ☞ Properly speaking, proof is the effect or result of evidence, evidence is the medium of proof.  Cf. Demonstration, 1.
 3. The quality or state of having been proved or tried; firmness or hardness that resists impression, or does not yield to force; impenetrability of physical bodies.
 4. Firmness of mind; stability not to be shaken.
 5. Print. A trial impression, as from type, taken for correction or examination; -- called also proof sheet.
 6. Math. A process for testing the accuracy of an operation performed.  Cf. Prove, v. t., 5.
 7. Armor of excellent or tried quality, and deemed impenetrable; properly, armor of proof. [Obs.]
 Artist's proof, a very early proof impression of an engraving, or the like; -- often distinguished by the artist's signature.
 Proof reader, one who reads, and marks correction in, proofs. See def. 5, above.
 Syn: -- Testimony; evidence; reason; argument; trial; demonstration. See Testimony.