Definition of "Device" :

noun: any clever maneuver

"He would stoop to any device to win a point."

noun: an instrumentality invented for a particular purpose

"The device is small enough to wear on your wrist."

noun: an emblematic design (especially in heraldry)

"He was recognized by the device on his shield."

noun: any ornamental pattern or design (as in embroidery)

noun: something in an artistic work designed to achieve a particular effect