(American football) In the AFL, a warning given with one minute to go before the end of a half, after which special rules apply, eg, stoppage of the game clock after very first down.

plural of black box warning

(UK) A form of all-points bulletin circulated to international ports so that a fleeing suspect can be identified and apprehended.

plural of two-minute warning

(meteorology, US) A warning issued by the United States National Weather Service that conditions are ideal for wildfires.

plural of red flag warning

plural of one-minute warning

plural of three-minute warning

plural of four-minute warning

(idiomatic) A UK Government public alert system in use during the Cold War to advise of an imminent nuclear attack. The "four-minute" adjective was not an accurate timing, but simply used as a euphemism to refer to the incoming attack as being from nuclear missiles.