Actuator (noun)

1. A device or mechanism for converting energy into motion.
2. A device that transforms an input signal into physical movement or action, especially in an automated system.

Origin:

Late 19th century: from actuate, on the pattern of earlier words such as motor.

Examples:

1. The actuator is responsible for moving the machine's arm.
2. The actuator converts electrical signals into mechanical movement.
3. The actuator is a key component in controlling the operation of the valve.
4. The actuator on the robot's arm allows it to grip objects.
5. The actuator is an important part of the control system for the aircraft.