Plain English Meaning
The actions a pilot takes on the controls to make the aircraft do what they want — turning the yoke, pushing the pedals, or moving the throttle.
Full Definition
The pilot's deliberate movements of the primary flight controls — yoke or stick, rudder pedals, and throttle — used to make the aircraft respond in a desired way. Each input commands a specific control surface or engine setting: aileron for roll, elevator for pitch, rudder for yaw, and throttle for power.