C19: from French servo-moteur, from Latin servus slave + French moteurmotor
servomotor in American English
(ˈsɜrvoʊˌmoʊtər)
noun
a device, as an electric motor, hydraulic piston, etc., that is controlled by an amplified signal from a command device of low power, as in a servomechanism
Word origin
< Fr servo-moteur < L servus, slave (see serf) + Fr moteur, motor