From BiblePortal Wikipedia
Webster's Dictionary 
(1): ( n.) The act of proving; also, that which proves anything; proof.
(2): ( n.) Any proceeding designed to ascertain truth, to determine character, qualification, etc.; examination; trial; as, to engage a person on probation.
(3): ( n.) The novitiate which a person must pass in a convent, to probe his or her virtue and ability to bear the severities of the rule.
(4): ( n.) The trial of a ministerial candidate's qualifications prior to his ordination, or to his settlement as a pastor.
(5): ( n.) Moral trial; the state of man in the present life, in which he has the opportunity of proving his character, and becoming qualified for a happier state.
Vine's Expository Dictionary of NT Words