The name of a law, established during the reign of the English king, William, the conquerer, by which the people were commanded to dispense with fire and candle at eight o'clock at night.

It was abolished in the reign of Henry I., but afterwards it signified the time at which the curfew formerly took place. The word curfew is derived, probably, from couvre few, or cover fire.

In modern times curfew refers to times when people are ordered to be off the streets in times of emergency. Also, a number of places have curfews that apply to people of certain ages.