A belt designed for a specific function, esp. for protection from falling, drowning, collision, etc. Cf… A safety belt in a motor vehicle…

a safety belt for a person in a moving conveyance, spec. one worn in an aircraft, esp. at take-off or landing, or one worn in a motor vehicle as a…

A belt in a motor vehicle to hold the wearer in his or her seat in the event of an emergency stop or collision. Cf. seat belt n. at seat, n.…

a safety belt across the lap.

a safety strap across the lap.

From their resemblance to the harness of a horse (see sense 4a above): straps so arranged that they can be fitted for the protection of…

a reel which enables a safety belt looped around it to be self-adjusting, esp. in inertia reel (safety) belt; also the belt served by the reel.