Controller /(?)/

Con·trol·ler

Controller

n.
  1. One who, or that which, controls or restraines; one who has power or authority to regulate or control; one who governs.
    The great controller of our fate Deigned to be man, and lived in low estate.
  2. An officer appointed to keep a counter register of accounts, or to examine, rectify, or verify accounts.
  3. An iron block, usually bolted to a ship's deck, for controlling the running out of a chain cable. The links of the cable tend to drop into hollows in the block, and thus hold fast until disengaged. (Naut.)
  4. Any electric device for controlling a circuit or system; (Elec.)
  5. A lever controlling the speed of an engine; -- applied esp. to the lever governing a throttle valve, as of a steam or gasoline engine, esp. on an automobile. (Mach.)