curfew [O.Fr., = cover fire], originally a signal, such as the ringing of a bell, to damp the fire, extinguish all lights in the dwelling, and retire for the night. The custom originated as a precaution against fires and was common throughout Europe in the Middle Ages. The curfew has most recently been used in times of turbulence, such as revolution or civil disorders. It is a restrictive measure forcing all persons into their homes to reduce activity against the government or the occupying force. In some communities it has been applied to curb juvenile delinquency.