A seatbelt is a safety device designed to secure a person in a vehicle or aircraft seat during a sudden or turbulent motion. It helps protect the occupant from being thrown forward or ejected during accidents or strong movements. In the case of the clue provided, the seatbelt icon lights up during a turbulent plane ride to remind passengers to fasten their seatbelts for added safety.
Note: The provided meaning of the answer is for the latest New York Times crossword puzzle clue: Icon that lights up during a turbulent plane ride. Explanations are generated by AI and may be inaccurate.