Definition of: penitentiary

(pen′ə·ten′shər·ē) noun plural ·ries
1. A prison, especially one operated by a state or government as a place of confinement and correction for those convicted of serious crimes.
2. One who prescribes or superintends penances; also, something that has to do with penances; specifically, in the Roman Catholic Church, an office, having at its head a cardinal (called the Grand Penitentiary), for deciding questions of conscience, absolution, special dispensation, etc.
—adjective
1. Pertaining to penance.
2. Relating to or used for the punishment and discipline of criminals.
3. Rendering the offender liable to imprisonment in a penitentiary. [<Med. L poenitentiarius <L poenitentia PENITENCE]