positioner vs actuator

positioner and actuator both are nouns.

Word	Noun	Adjective	Verb	Adverb
positioner	Yes	No	No	No
actuator	Yes	No	No	No

As nouns, actuator is a hypernym of positioner; that is, actuator is a word with a broader meaning than positioner:

positioner: (computer science) the actuator that moves a read/write head to the proper data track
actuator: a mechanism that puts something into automatic action

positioner (noun)	actuator (noun)
(computer science) the actuator that moves a read/write head to the proper data track	a mechanism that puts something into automatic action
a device used to control the opening or closing of the actuator based on electric, or pneumatic signals.