noun

• One who controls something.
• (electronics) Any electric or mechanical device for controlling a circuit or system.
• (business) The chief accounting officer which audits, and manages the financial affairs of a company or government; a comptroller.
• (computer hardware) A mechanism that controls or regulates the operation of a machine, especially a peripheral device in a computer.
• (video games) A hardware device designed to allow the user to play video games.
• (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.
• (espionage) The person who supervises and handles communication with an agent in the field.
• (linguistics) The subject of a control verb. See Control (linguistics)
• (software architecture) In software applications using the model-view-controller design pattern, the part or parts of the application that treat input and output, forming an interface between models and views.