What are the large, side body sections that extend from the side doors back to the rear bumper called?

The large side body sections that extend from the side doors to the rear bumper are referred to as quarter panels. These panels form the rear part of a vehicle's body structure, providing support and shaping for the car's design. They also play a crucial role in protecting the internal components of the car from external elements and impacts. In many vehicle designs, the quarter panel houses features such as the rear lights or trunk opening, further contributing to both function and aesthetics.

Fenders, while also part of the body structure, are located at the front and rear of the vehicle, covering the wheel wells, and do not extend from the doors to the bumper in the same manner. Rockers are the horizontal panels located beneath the door area of the car, adding structural support and protection. Skirt panels are often associated with aftermarket modifications or aesthetic enhancements and typically extend along the sides of the vehicle, but they do not define the large sections from the doors to the rear bumper as accurately as quarter panels do.