NOUN (3)

1. a trial period during which your character and abilities are tested to see whether you are suitable for work or for membership;

2. a trial period during which an offender has time to redeem himself or herself;

3. (law) a way of dealing with offenders without imprisoning them; a defendant found guilty of a crime is released by the court without imprisonment subject to conditions imposed by the court;
- Example: "probation is part of the sentencing process"

The Collaborative International Dictionary of English v.0.48:

Probation \Pro*ba"tion\, n. [L. probatio, fr. probare to try,
   examine, prove: cf. F. probation. See Prove.]
   [1913 Webster]
   1. The act of proving; also, that which proves anything;
      proof. [Obs.]
      [1913 Webster]

            When by miracle God dispensed great gifts to the
            laity, . . . he gave probation that he intended that
            all should prophesy and preach.       --Jer. Taylor.
      [1913 Webster]

   2. Any proceeding designed to ascertain truth, to determine
      character, qualification, etc.; examination; trial; as, to
      engage a person on probation. Hence, specifically:
      (a) 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.
      (b) The trial of a ministerial candidate's qualifications
          prior to his ordination, or to his settlement as a
          pastor.
      (c) 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.
          [1913 Webster]

                No [view of human life] seems so reasonable as
                that which regards it as a state of probation.
                                                  --Paley.
          [1913 Webster]

WordNet (r) 3.0 (2006):

probation
    n 1: a trial period during which your character and abilities
         are tested to see whether you are suitable for work or for
         membership
    2: a trial period during which an offender has time to redeem
       himself or herself
    3: (law) a way of dealing with offenders without imprisoning
       them; a defendant found guilty of a crime is released by the
       court without imprisonment subject to conditions imposed by
       the court; "probation is part of the sentencing process"

Moby Thesaurus II by Grady Ward, 1.0:

25 Moby Thesaurus words for "probation":
   acid test, assay, blank determination, brouillon, criterion,
   crucial test, crucible, determination, docimasy, essay,
   feeling out, first draft, kiteflying, ordeal, proof, rough draft,
   rough sketch, sounding out, standard, test, test case, touchstone,
   trial, try, verification



Bouvier's Law Dictionary, Revised 6th Ed (1856):

PROBATION. The evidence which proves a thing. It is either by record,
writing, the party's own oath, or the testimony of witnesses. Proof. (q.v.)
It also signifies the time of a novitiate; a trial.  Nov. 5.