curfew

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A regulation requiring certain or all people to leave the streets or be at home at a prescribed hour.
2. n. The time at which such a restriction begins or is in effect: a 10 P.M. curfew for all residents.
3. n. The signal, such as a bell, announcing the beginning of this restriction.

Century Dictionary and Cyclopedia

1. n. The ringing of a bell at an early hour (originally 8 o'clock) in the evening, as a signal to the inhabitants of a town or village to extinguish their fires and lights; the time of ringing the bell; the bell so rung, or its sound. This was a very common police regulation during the middle ages, as a protection against fires as well as against nocturnal disorders in the unlighted streets. The practice is commonly said to have been introduced into England from the continent by William the Conqueror, but it probably existed there before his time. The curfew-bell is still rung at 9 o'clock in some places, though it is several centuries since it was required by law.
2. n. A cover, ornamented or plain, for a fire; a fire-plate; a blower.

Wiktionary

1. n. historical A regulation in feudal Europe by which fires had to be covered up or put out at a certain fixed time in the evening, marked by the ringing of an evening bell.
2. n. The evening bell, which continued to be rung in many towns after the regulation itself became obsolete.
3. n. Any regulation requiring people to be off the streets and in their homes by a certain time.
4. n. The time when such restriction begins.
5. n. A signal indicating this time.
6. n. A fireplace accessory designed to bank a fire by completely covering the embers.

GNU Webster's 1913

1. n. The ringing of an evening bell, originally a signal to the inhabitants to cover fires, extinguish lights, and retire to rest, -- instituted by William the Conqueror; also, the bell itself.
2. n. obsolete A utensil for covering the fire.

WordNet 3.0

1. n. a signal (usually a bell) announcing the start of curfew restrictions
2. n. an order that after a specific time certain activities (as being outside on the streets) are prohibited
3. n. the time that the curfew signal is sounded