1. a safety strap in a vehicle that holds a person securely in their seat

Examples

• Please fasten your seatbelt before we start driving.
• The flight attendant reminded passengers to keep their seatbelts fastened during turbulence.
• She always checks that her children have their seatbelts on properly.
• The car won’t start until everyone’s seatbelt is buckled.
• He was fined for not wearing his seatbelt while driving.
• The seatbelt saved her life in the accident.