What is "proof reader"

Proof \Proof\, n. [OF. prove, proeve, F. preuve, fr. L. proba, fr. probare to prove. See Prove.]

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.]
   --Shak.

   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.

alt. A person who reads proof, copy or other text, looking for errors and making corrections n. A person who reads proof, copy or other text, looking for errors and making corrections