broken arrow

noun2

1. •
   (US, historical) Any of a series of accidental nuclear events in the Cold War, involving nuclear weapons or warheads fallen from aircrafts, which could have triggered a nuclear war.
2. •
   A callout marker that consists of a dashed line with an arrowhead.

   • A broken arrow A - - -> B indicates that an occasional result of Section A is used in Section B, but that Section B is essentially independent of Section A. — 2003

noun1

1. •
   (US, euphemistic) An accidental event that involves nuclear weapons or nuclear components but does not create the risk of nuclear war.

phrase1

1. •
   (US) A code phrase indicating that a ground unit is facing imminent destruction from enemy attack and all available air forces within range are to provide air support immediately.

   • The FAC urgently sends over his radio a cry for help: "Broken Arrow! Broken Arrow!' His message unleashes all available close air support in South Vietnam on a priority basis. — 2003