A prison (from Old French prisoun), also known as gaol or jail, is a place in which people are physically confined and usually deprived of a range of personal freedoms. Imprisonment or incarceration is a legal penalty that may be imposed by the government for the commission of a crime. Other terms used are penitentiary, correctional facility, remand centre, detention centre, and gaol or jail. In some legal systems some of these terms have distinct meanings.
A criminal suspect who has been charged with or is likely to be charged with criminal offense or Offence may be held on remand in prison if he or she is denied or unable to meet conditions of bail, or is unable or unwilling to post bail. A criminal defendant may also be held in prison while awaiting trial or a trial verdict. If found guilty, a defendant will be convicted and may receive a custodial sentence requiring imprisonment.
As well as convicted or suspected criminals, prisons may be used for internment of those not charged with a crime. Prisons may also be used as a tool of political repression to detain political prisoners, prisoners of conscience, and "enemies of the state", particularly by authoritarian regimes. In times of war or conflict, prisoners of war may also be detained in prisons. A prison system is the organizational arrangement of the provision and operation of prisons.