A curfew is an order specifying a time during which certain regulations apply. Examples:
1. An order issued by the public authorities or military insurgents requiring everyone or certain people to be indoors at certain times, often at night. It can be imposed to maintain public order (such as those after the Northeast Blackout of 2003, the 2005 civil unrest in France, the 2010 Chile earthquake and 2011 Egyptian revolution), or suppress targeted groups. Curfews have long been directed at certain groups in many cities or states, such as Japanese-American university students on the West Coast of the United States during World War II, African-Americans in many towns during the time of Jim Crow laws, or people younger than a certain age (usually within a few years either side of 18) in many towns of the United States since the 1980s; see below.
2. An order by the legal guardians of a teenager to return home by a specific time, usually in the evening or night. This may apply daily, or vary with the day of the week, e.g., if the minor has to go to school the next day.
3. A daily requirement for guests to return to their hostel before a specified time, usually in the evening or night.
4. In baseball, a time after which a game must end, or play be suspended. For example, in the American League the curfew rule for many years decreed that no inning could begin after 1 am local time (with the exception of international games).
5. In aeronautics, night flying restrictions may restrict aircraft operations over a defined period in the nighttime, to limit the disruption of aircraft noise on the sleep of nearby residents. Notable examples are the London airports of Heathrow, Gatwick and Stansted, which operate under the Quota Count system.
6. In a few locations in the UK patrons of licensed premises may not enter after a "curfew" time. In Inverclyde for example this is currently set at 11:30 pm.