noun one who does penance.
2. penitentiary ·adj used for punishment, discipline, and reformation.
3. penitentiary ·adj expressive of penitence; as, a penitentiary letter.
4. penitentiary ·noun one who prescribes the rules and measures of penance.
5. penitentiary ·noun that part of a church to which penitents were admitted.
6. penitentiary ·noun a small building in a monastery where penitents confessed.
7. penitentiary ·adj relating to penance, or to the rules and measures of penance.
8. penitentiary ·noun an officer in some dioceses since ·a.d. 1215, vested with power from the bishop to absolve in cases reserved to him.
9. penitentiary ·noun a house of correction, in which offenders are confined for punishment, discipline, and reformation, and in which they are generally compelled to labor.
10. penitentiary ·noun 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.