a belt or strap in an automobile, airplane, etc., fastened around or sometimes diagonally across the midsection to keep the person safely secured, as during a sudden stop.
Compare lap belt.
Origin of seat belt
First recorded in 1945–50
Also called safety belt.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for seat belt
Also called: safety belt a belt or strap worn in a vehicle to restrain forward motion in the event of a collision
a similar belt or strap worn in an aircraft at takeoff and landing and in rough weather
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012