Pronunciation: (prOOf), [key]
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. 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.

1. able to withstand; successful in not being overcome: proof against temptation.
2. impenetrable, impervious, or invulnerable: proof against outside temperature changes.
3. used for testing or proving; serving as proof.
4. of standard strength, as an alcoholic liquor.
5. of tested or proven strength or quality: proof armor.
6. noting pieces of pure gold and silver that the U.S. assay and mint offices use as standards.

1. to test; examine for flaws, errors, etc.; check against a standard or standards.
2. Print.prove (def. 7).
3. to proofread.
4. 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.
5. 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.


a combining form meaning “resistant, impervious to” that specified by the initial element: burglarproof; childproof; waterproof.

Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.

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