controller

1. (electronics) Any electric or mechanical device for controlling a circuit or system.Examples: "Nothing more can be squeezed out of the motive power unit once the master controller has been moved to full on."

2. (business) The chief accounting officer which audits, and manages the financial affairs of a company or government; a comptroller.

3. (computer hardware) A mechanism that controls or regulates the operation of a machine, especially a peripheral device in a computer.Synonyms: driver

4. (video games) A hardware device designed to allow the user to play video games.Examples: "I'm collecting player's names for a school project. You know, players just like you! That's right, you--the one holding the controller. Would you register your name, please?"Synonyms: game controller

5. (nautical) 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.

6. (espionage) The person who supervises and handles communication with an agent in the field.