Martial law is a specified form of government and law enforcement.
It is defined as
1) Temporary rule by military authorities, imposed on a civilian population especially in time of war or emergency, when civil authority has broken down. It may also be used during outbreaks of deadly illnesses.
2) The law imposed on an occupied territory by occupying military forces.
Among aspects of martial law are censorship of radio and newspapers, prohibition of the sale and consumption of alcoholic beverages, prohibition of gatherings of more than five persons in the street, and requirement of a permit from the local military authorities before any public meeting can be held. Religious meetings inside buildings may be tolerated by the authorities, held at hours not conflicting with the curfew.
In rare cases, martial law has been in effect with armed soldiers barring citizens from being out-of-doors after sunset.
Martial law is used when the government calls for a state of emergency. Martial law is used as curfew, crowd control, and when looting is taking place. It is also known as a police action.
*The US television series Martial Law (1998-2000) was an action police series starring Hong Kong actor Sammo Hung. The title was a wordplay on the leading character's name, "Marshal" Sammo Law.