Source : Webster's Revised Unabridged Dictionary (1913)

Penitentiary \Pen`i*ten"tia*ry\, a. [Cf. F. p['e]nitentiaire.]
   1. Relating to penance, or to the rules and measures of
      penance. ``A penitentiary tax.'' --Abp. Bramhall.

   2. Expressive of penitence; as, a penitentiary letter.

   3. Used for punishment, discipline, and reformation.
      ``Penitentiary houses.'' --Blackstone.

Penitentiary \Pen`i*ten"tia*ry\, n.; pl. {Penitentiaries}. [Cf.
   F. p['e]nitencier. See {Penitent}.]
   1. One who prescribes the rules and measures of penance.
      [Obs.] --Bacon.

   2. One who does penance. [Obs.] --Hammond.

   3. A small building in a monastery where penitents confessed.
      --Shpiley.

   4. That part of a church to which penitents were admitted.
      --Shipley.

   5. (R. C. Ch.)
      (a) An office of the papal court which examines cases of
          conscience, confession, absolution from vows, etc.,
          and delivers decisions, dispensations, etc. Its chief
          is a cardinal, called the Grand Penitentiary,
          appointed by the pope.
      (b) An officer in some dioceses since A. D. 1215, vested
          with power from the bishop to absolve in cases
          reserved to him.

   6. A house of correction, in which offenders are confined for
      punishment, discipline, and reformation, and in which they
      are generally compelled to labor.

Source : WordNet®

penitentiary
     adj : used for punishment or reform of criminals or wrongdoers;
           "penitentiary institutions"
     n : a correctional institution for those convicted of major
         crimes [syn: {pen}]