Prison
Part of speech: noun
Definition: A place of long-term confinement for those convicted of serious crimes. Confinement in a prison. Any restrictive environment, such as a harsh academy or home.
Penitentiary
Part of speech: noun
Definition: A state or federal prison for convicted felons.(Roman Catholic Church) A priest who administers the sacrament of penance.
Part of speech: adjective
Definition: of, or related to penance; penitentialof, or relating to the punishment of criminals