There is a small difference under this question. Some people think that the servo motor is actually a system, while others think that the servo motor is really a motor.

In my opinion, they are all right. The difference here is mainly how to define the motor.

From the principle point of view, only the most core stator rotor is regarded as a motor, and the servo motor is of course a system because the servo control circuit is outside the motor.

If you look at the classification of equipment, the entire housing is considered a motor. The servo motor is a separate motor.

Actually, in our life, it does not require a particularly strict definition as it does for theoretical research. At least on the point of what the servo motor is, it is impossible for someone to sell  a motor without t
he core of the servo circuit.