1) Actuator 2) Rotary actuator 
physical unit combining an actuating drive and the final controlling element mechanically actuated by the actuating drive NOTE - Positioners are used only in conjunction with mechanically actuated final controlling elements.
A field based device that takes a signal from a control system and ensures that the control device is at the setting required by the control system.
A resilient elastoplastic or rubber removable appliance fitting over the occlusal surface of the teeth, to obtain limited tooth movement and/or stabilization, usually used at the end of orthodontic treatment. ... (05 Mar 2000) ... 
Type: Term Pronunciation: pŏ-zish′ŭn-ĕr Definitions: 1. A resilient elastoplastic or rubber removable appliance fitting over the occlusal surface of the teeth, to limit tooth movement or provide stabilization, usually used at the end of orthodontic treatment.