A curfew is an order specifying a time during which certain regulations apply. Typically it is the time when individuals must stay indoors. Such an order may be issued by public authorities but also by the owner of a house to those living in the household. For instance, an au pair is typically given a curfew, which regulates when they must return to the host family's home in the evening. Curfews are a common element of control used in martial law, though curfews can also be implemented for public safety in the event of a disaster, pandemic, or crisis.