Plain English Meaning

Servos are the little motors the autopilot uses to actually move the controls. When the autopilot decides the aircraft needs to turn or pitch up, the servos do the muscle work the pilot would normally do with the yoke and rudder pedals.

Full Definition

In an autopilot system, servos are the small electric or electro-pneumatic motors that physically move the aircraft's flight controls — typically the ailerons, elevator, and sometimes the rudder or trim — in response to commands from the autopilot computer. They convert the autopilot's electrical signals into the mechanical force needed to deflect a .