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 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.