Other forms: seatbelts
A seatbelt is the strap you click across your body before the car moves. Fasten your seatbelt, wear a seatbelt, the seatbelt light.
The three-point belt was designed by Nils Bohlin at Volvo in 1959, and the company gave the patent away so that everybody could use it — which is credited with saving an enormous number of lives. It has been compulsory in the front in Britain since 1983 and in the back since 1991. Note seatbelt sign; and that a belt works by spreading force across the strongest parts of the body.
1nounseatbeltThe strap fastened across the body in a vehicle.
“Please fasten your seatbelt before the car moves.”
seatbelt is a safety restraint.
Also accepted in games: seat belt
From seat + belt. seat + belt.
Etymology from Wiktionary, CC BY-SA