Safety
Safety is the condition of being protected against failure, breakage, error or accidents. Protection involves here both causing and exposure.
See also
In American football, a safety is the act by which one team gains two points when an opponent possessing the ball is tackled in his own end zone, or runs out of bounds in his own end zone. Additionally, safety refers to two positions in the traditional defensive backfield setup, the strong safety and the free safety.
In firearms, a safety or safety catch is a device which inactivates the trigger, making the firearm safe to handle.