Definitions of proof:

• noun:   a trial photographic print from a negative
• noun:   any factual evidence that helps to establish the truth of something

  Example: "If you have any proof for what you say, now is the time to produce it"

• noun:   (printing) an impression made to check for errors
• noun:   a formal series of statements showing that if one thing is true something else necessarily follows from it
• noun:   a measure of alcoholic strength expressed as an integer twice the percentage of alcohol present (by volume)
• noun:   the act of validating; finding or testing the truth of something
• verb:   activate by mixing with water and sometimes sugar or milk

  Example: "Proof yeast"

• verb:   knead to reach proper lightness

  Example: "Proof dough"

• verb:   make resistant to water, sound, errors, etc.

  Example: "Proof the materials against shrinking in the dryer"

• verb:   make or take a proof of, such as a photographic negative, an etching, or typeset
• verb:   read for errors

  Example: "I should proofread my manuscripts"