Definition: A small mechanism inside the RC vehicle, the servo is a device with a motor, gears, and circuits that controls things like steering and speed. The servo has a rotating shaft that connects to a servo arm that connects to rods or other parts (linkage) to control various parts of the RC.
Number of Servos: A typical RC car has a steering servo to make the wheels turn and a speed control or throttle servo to make it go faster or slower. Other types of servos may be present to control other functions. The servos plug into the receiver on a hobby-grade RC. In RC toys, the servo connections are soldered to the circuit board inside the RC.