What does "control surface" refer to in aerodynamics?

The term "control surface" in aerodynamics specifically refers to the movable aerodynamic components of an aircraft that are designed to manipulate its attitude and trajectory during flight. These surfaces include ailerons, elevators, and rudders, which actively change the airflow around the aircraft to produce the necessary forces for controlling pitch, roll, and yaw.

This function is essential for pilot input on controlling the flight path, making "movable aerodynamic surfaces that control aircraft movements" the accurate definition. While static surfaces contribute to overall flight stability, they do not perform the active role that control surfaces do. The options relating to parts of the engine or fixed structures do not pertain to the defined role of control surfaces, which are specifically designed for maneuverability rather than support or thrust management.