—n. 1. a place for imprisonment, reformatory discipline, or punishment, esp. a prison maintained in the U.S. by a state or the federal government for serious offenders.
2. Rom. Cath. Ch.a tribunal in the Curia Romana, presided over by a cardinal (grand penitentiary), having jurisdiction over certain matters, as penance, confession, dispensation, absolution, and impediments, and dealing with questions of conscience reserved for the Holy See.
—adj. 1. (of an offense) punishable by imprisonment in a penitentiary.
2. of, pertaining to, or intended for imprisonment, reformatory discipline, or punishment.