What is what does broken arrow mean?

Broken Arrow is a military term used to describe an emergency situation that arises in which a nuclear weapon or nuclear weapon component is lost, stolen, or accidentally released. This may refer to a situation where a nuclear weapon is dropped, damaged or destroyed, or when a plane carrying a nuclear weapon crashes.

The term "Broken Arrow" was originally an American military code name for a missing or lost nuclear weapon. The term has since been adopted by other countries' military as well. In the event of a Broken Arrow situation, emergency response protocols and procedures are implemented quickly to minimize the damage caused by the incident and to safely secure the nuclear weapon or component.