A prison, also known as a jail, gaol, penitentiary, detention center, correction center, correctional facility, or remand center, is a facility where people are imprisoned under the authority of the state, usually as punishment for various crimes. They may also be used to house those awaiting trial (pre-trial detention). Prisons serve two primary functions within the criminal-justice system: holding people charged with crimes while they await trial, and confining those who have pleaded guilty or been convicted to serve out their sentences.
Prisons can also be used as a tool for political repression by authoritarian regimes who detain perceived opponents for political crimes, often without a fair trial or due process; this use is illegal under most forms of international law governing fair administration of justice. In times of war, belligerents or neutral countries may detain prisoners of war or detainees in military prisons or in prisoner-of-war camps. At any time, states may imprison civilians – sometimes large groups of civilians – in internment camps.
