Possible Definitions:
1. Controller (n.) One who, or that which, controls or restraines; one who has power or authority to regulate or control; one who governs.
2. Controller (n.) An officer appointed to keep a counter register of accounts, or to examine, rectify, or verify accounts.
3. Controller (n.) 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.
4. Controller (n.) Any electric device for controlling a circuit or system;
5. Controller (n.) An electromagnet, excited by the main current, for throwing a regulator magnet into or out of circuit in an automatic device for constant current regulation.
6. Controller (n.) A kind of multiple switch for gradually admitting the current to, or shutting it off from, an electric motor; as, a car controller for an electric railway car.
7. Controller (n.) 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.
