What is what does an a with a circle around it mean in a car?

The "A" with a circle around it in a car typically represents the Auto Start-Stop system. This system is designed to improve fuel efficiency by automatically shutting off the engine when the car is stationary, such as at a traffic light, and then restarting it when the driver releases the brake pedal or presses the accelerator.

Sometimes, the "A" will have a line through it, which indicates that the Auto Start-Stop system is disabled or unavailable due to various factors, such as low battery charge, engine temperature, or other system requirements not being met.