proof

/proohf/, n.

1. evidence sufficient to establish a thing as true, or to produce belief in its truth.

2. anything serving as such evidence: What proof do you have?

3. the act of testing or making trial of anything; test; trial: to put a thing to the proof.

4. the establishment of the truth of anything; demonstration.

5. Law. (in judicial proceedings) evidence having probative weight.

6. the effect of evidence in convincing the mind.

7. an arithmetical operation serving to check the correctness of a calculation.

8. Math., Logic. a sequence of steps, statements, or demonstrations that leads to a valid conclusion.

9. a test to determine the quality, durability, etc., of materials used in manufacture.

10. Distilling.

a. the arbitrary standard strength, as of an alcoholic liquor.

b. strength with reference to this standard: "100 proof" signifies a proof spirit, usually 50% alcohol.

11. Photog. a trial print from a negative.

12. Print.

a. a trial impression, as of composed type, taken to correct errors and make alterations.

b. one of a number of early and superior impressions taken before the printing of the ordinary issue: to pull a proof.

13. (in printmaking) an impression taken from a plate or the like to show the quality or condition of work during the process of execution; a print pulled for examination while working on a plate, block, stone, etc.

14. Numis. one of a limited number of coins of a new issue struck from polished dies on a blank having a polished or matte surface.

15. the state of having been tested and approved.

16. proved strength, as of armor.

17. Scot. Law. the trial of a case by a judge alone, without a jury.

adj.

18. able to withstand; successful in not being overcome: proof against temptation.

19. impenetrable, impervious, or invulnerable: proof against outside temperature changes.

20. used for testing or proving; serving as proof.

21. of standard strength, as an alcoholic liquor.

22. of tested or proven strength or quality: proof armor.

23. noting pieces of pure gold and silver that the U.S. assay and mint offices use as standards.

v.t.

24. to test; examine for flaws, errors, etc.; check against a standard or standards.

25. Print. prove (def. 7).

26. to proofread.

27. to treat or coat for the purpose of rendering resistant to deterioration, damage, etc. (often used in combination): to proof a house against termites; to shrink-proof a shirt.

28. Cookery.

a. to test the effectiveness of (yeast), as by combining with warm water so that a bubbling action occurs.

b. to cause (esp. bread dough) to rise due to the addition of baker's yeast or other leavening.

[1175-1225; ME prove, prooff, prof, proufe, alter. (by assoc. with the vowel of PROVE) of preove, proeve, prieve, pref < MF preve, proeve, prueve < LL proba a test, akin to L probare to test and find good; cf. PREE]

Syn. 1. confirmation, demonstration, corroboration, support. See evidence. 3. examination, assay. 18. firm, steadfast.

* * *

In logic and mathematics, an argument that establishes a proposition's validity.

Formally, it is a finite sequence of formulas generated according to accepted rules. Each formula either is an axiom or is derived from a previously established theorem, and the last formula is the statement that is to be proven. The essence of deductive reasoning (see deduction), this is the basis of Euclidean geometry and all scientific methods inspired by it. An alternative form of proof, called mathematical induction, applies to propositions defined through processes based on the counting numbers. If the proposition holds for n = 1 and can be shown to hold for n = k + 1 whenever n = k (a constant) is also true, then it holds for all values of n. An example is the assertion that the sum of the first n counting numbers is n(n + 1)/2.

* * *

▪ liquor

      in liquor distilling, a measure of the absolute alcohol content of a distilled liquor, which is a mixture of alcohol and water. The measurement is made by determining the specific gravity of the liquor; that is, the weight per unit volume of the liquid compared to that of water. The measurement of the alcohol content is expressed in terms that vary from country to country: specific gravity, percentage by volume of alcohol, percentage by weight of alcohol, percentage by volume of proof spirit, or by gradations on an arbitrary scale. The measurement is done at an index temperature, as specific gravity varies with temperature.

      In Great Britain, the Customs and Excise Act of 1952, declared proof spirits (100 proof ) to be those in which the weight of the spirits is ¹²/₁₃ the weight of an equal volume of distilled water at 51° F (11° C). Thus, proof spirits are 48.24 percent alcohol by weight or 57.06 percent by volume. Other spirits are designated over or under proof, with the percentage of variance noted. In the United States, a proof spirit (100 proof) is one containing 50 percent alcohol by volume.

▪ logic

      in logic, an argument that establishes the validity of a proposition. Although proofs may be based on inductive logic, in general the term proof connotes a rigorous deduction. In formal axiomatic systems of logic and mathematics, a proof is a finite sequence of well-formed formulas (generated in accordance with accepted formation rules) in which: (1) each formula is either an axiom or is derived from some previous formula or formulas by a valid inference; and (2) the last formula is that which is to be proved. For proof by cases, see dilemma.

* * *