Meaning

noun a correctional institution for those convicted of major crimes

adjective used for punishment or reform of criminals or wrongdoers

adjective showing or constituting penance

originFrom Middle English penitentiary, from Medieval Latin pēnitentiārius (“place of penitence”), from Latin paenitentia (“penitence”), term used by the Quakers in Pennsylvania during the 1790s, describing a place for penitents to dwell upon their sins.

Etymology from Wiktionary, CC BY-SA 3.0