Definitions of device:

• noun:   any clever (deceptive) maneuver

  Example: "He would stoop to any device to win a point"

• noun:   an instrumentality invented for a particular purpose

  Example: "The device is small enough to wear on your wrist"

• noun:   an emblematic design (especially in heraldry)

  Example: "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