Emily Dickinson Lexicon

PROOF, n. [Sax. profian, to prove; Sw. prof, proof; Dan. pröve, D. proef; G. probe; W. praw; Fr. preuve; It. prova; Sp. prueba; Russ. proba. See Prove.]

1. Trial; essay; experiment; any effort, process or opration that ascertains truth or fact. Thus the quality of spirit is ascertained by proof; the strength of gunpowder, of firearms and of cannon is determined by proof; the correctness of operations in arithmetic is ascertained by proof.
2. In law and logic, that degree of evidence which convinces the mind of the certainty of truth or fact, and produces belief. Proof is derived from personal knowledge, or from the testimony of others, or from conclusive reasoning. Proof differs from demonstration, which is applicable only to those truths of which the contrary is inconceivable. This has neither evidence of truth, nor proof sufficient to give it warrant. – Hooker.
3. Firmness or hardness that resists impression, or yields not to force; impenetrability of physical bodies; as, a wall that is proof against shot. See arms of proof. – Dryden.
4. Firmness of mind; stability not to be shaken; as, a mind or virtue that is proof against the arts of seduction and the assaults of temptation.
5. The proof of spirits consists in little bubbles which appear on the top of the liquor after agitation, called the bead, and by the French, chapelet. Hence,
6. The degree of strength in spirit; as, high proof; first proof; second, third, or fourth proof.
7. In printing and engraving, a rough impression of a sheet, taken for correction; plur. proofs, not proves.
8. Armor sufficiently firm to resist impression. [Not used.] – Shak. Proof is used elliptically for of proof. I have found thee / Proof against all temptation. – Milton. It is sometimes followed by to, more generally by against. Proof-impression, an early impression of an engraving, considered the best as being first taken.