The word "curfew" is derived from the French "couvre-feu," meaning "cover fire."

The ringing of the curfew originated in England by William the Conqueror, who directed that at the ringing of the bell at eight o'clock all fires and lights should be extinguished. The law was repealed by Henry I in 1100, but the bell continued to be rung in many districts to modern times and probably may still be heard.

The name was also given formerly to a domestic utensil for covering up a fire.

In the United States an ordinance establishing a curfew, with the purpose of keeping young people off the streets, has existed in Salem, Mass., since Puritan days.

Similar ordinances have of late been adopted in other cities, in general providing that children under fifteen shall not frequent the streets after nine o'clock in summer and eight in winter.