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. Prisons are most commonly used within a criminal-justice system by authorities: people charged with crimes may be imprisoned until their trial; and those who have pleaded or been found guilty of crimes at trial may be sentenced to a specified period of imprisonment.