What does 'on' mean on a car?

[StMadelyn]

On a car, 'on' means to turn on. By rotating the key to the 'on' position, the car's electrical system is powered. If you continue to turn the key to the 'start' position, the engine will start. After turning to the 'on' position, all electrical devices in the car can be used. In the car's ignition switch system, there are four positions, and 'on' is one of them. This switch, when activated, keeps the vehicle in a ready-to-start state while driving, known as the car's preparation function. For example, if a driver forgets to close the windows after parking and the car is already turned off, they can turn the key to the 'on' position to power the car's electrical system and close the windows without restarting the vehicle. Besides keeping the car in a powered state, the 'on' position also has a self-check function. It allows the car to perform a self-diagnosis on the engine, brake system, etc., before starting. If no faults are detected, the self-check lights on the dashboard will automatically turn off.