ˈ ̷ ̷ ̷ ̷ˌwād.ə(r), -ātə- noun
( -s )
: one that actuates ; specifically : any of various electric, hydraulic, or pneumatic mechanisms by means of which something is moved or controlled indirectly instead of by hand (as a motor that turns the rudder of a large ship or moves the elevators of an airplane or an air-brake cylinder operated by a motorman)