Merriam-Webster Collegiate Dictionary - proof

 I. noun  Etymology: Middle English prof, prove, alteration of preve, from Anglo-French preove, from Late Latin proba, from Latin probare to prove — more at prove  Date: 13th century  1.  a. the cogency of evidence that compels acceptance by the mind of a truth or a fact  b. the process or an instance of establishing the validity of a statement especially by derivation from other statements in accordance with principles of reasoning  2. obsolete experience  3. something that induces certainty or establishes validity  4. archaic the quality or state of having been tested or tried; especially unyielding hardness  5. evidence operating to determine the finding or judgment of a tribunal  6.  a. plural ~s or ~ a copy (as of typeset text) made for examination or correction  b. a test impression of an engraving, etching, or lithograph  c. a coin that is struck from a highly polished die on a polished planchet, is not intended for circulation, and sometimes differs in metallic content from coins of identical design struck for circulation  d. a test photographic print made from a negative  7. a test applied to articles or substances to determine whether they are of standard or satisfactory quality  8.  a. the minimum alcoholic strength of ~ spirit  b. strength with reference to the standard for ~ spirit; specifically alcoholic strength indicated by a number that is twice the percent by volume of alcohol present whiskey of 90 ~ is 45 percent alcohol  II. adjective  Date: 1592  1. able to resist or repel boots that were…~ against cold and wet — Robertson Davies — often used in combination wind~  2. used in proving or testing or as a standard of comparison  3. of standard strength or quality or alcoholic content  III. transitive verb  Date: 1745  1.  a. to make or take a ~ or test of  b. ~read  2. to give a resistant quality to  3. to activate (yeast) by mixing with water and sometimes sugar or milk  • ~er noun