WordDictionary

Adjective:

• Being of a certain standard as to strength; -- said of alcoholic liquors.
• Firm or successful in resisting; as, proof against harm; waterproof; bombproof.
• Used in proving or testing; as, a proof load, or proof charge.

Noun:

• Any effort, process, or operation designed to establish or discover a fact or truth; an act of testing; a test; a trial.
• Firmness of mind; stability not to be shaken.
• mathematics A sequence of statements consisting of axioms, assumptions, statements already demonstrated in another proof, and statements that logically follow from previous statements in the sequence, and which concludes with a statement that is the object of the proof.
• mathematics A process for testing the accuracy of an operation performed. Compare prove, ''transitive verb'', 5.
• obsolete: Armour of excellent or tried quality, and deemed impenetrable; properly, armour of proof.
• printing A proof sheet; a trial impression, as from type, taken for correction or examination.
• The degree of evidence which convinces the mind of any truth or fact, and produces belief; a test by facts or arguments which induce, or tend to induce, certainty of the judgment; conclusive evidence; demonstration.
• The quality or state of having been proved or tried; firmness or hardness which resists impression, or doesn't yield to force; impenetrability of physical bodies.
• US A measure of the alcohol content of liquor. Originally, in Britain, 100 '''proof''' was defined as 57.1% by volume (not used anymore). In the US, 100 '''proof''' means that the alcohol content is 50% of the total volume of the liquid, and thus, absolute alcohol would be 200 '''proof'''.

Verb:

• intransitive|colloquial To proofread.
• transitive To knead, as in bread dough.
• transitive To make resistant, especially to water.