What is meant by servo mechanism?

Servomechanism is the combination of set of devices using for precision activities like movement, triggering, aiming by acting in a closed loop system by comprising an input device, a processor, a module to analyse feedback, prime mover like servomotor, a sensor for giving feedback. In each incremental motion a position feedback is sent to processor to analyse to deliver an instruction to module such that position value - feedback incremental value is the current position which will loop until target value become null.