The word "servo" are used for the situation that objects move to the target position or follow a moving objective.
The word "servo" comes from the Latin word, servos, which means slave, and a "servomechanism"( "servo" for short).
Servo is a control system that control machine as issued commands.
Servo mechanism enables the position, speed, torque control or combinations of these controls.

Position control Speed control Torque control
Servos accurately move objects or stop them at a set position.
Servos can even positioning objects at submicron precision (μm = 1/1000 mm), and repeatedly start/stop objects.		 Servos highly response to the target speed even when the speed changes.
Servos can also minimize the speed difference from the target speed when the load changes.
Continuous operation is possible at wide range of speed.		 Servos accurately control the torque even when the load changes.
*Torque is the force that produces rotation.