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.
1. One who prescribes the rules and measures of penance. [Obs.] Bacon. 2. One who does penance. [Obs.] Hammond. 3. A ...