9 Grammatical Pitfalls


[kuh n-troh-ler] /kənˈtroʊ lər/
an employee, often an officer, of a business firm who checks expenditures, finances, etc.; comptroller.
a person who regulates, directs, or restrains.
British Aeronautics. a dispatcher.
a regulating mechanism; governor.
Also called control unit, processor. Computers. the key component of a peripheral device, as a terminal, printer, or external storage unit, that contains the circuitry necessary to interpret and execute instructions fed into the device.
Origin of controller
1350-1400; Middle English countrollour < Anglo-French countrero(u)llour, Middle French contrerolleur, equivalent to contrerolle duplicate roll (see control) + -eur, -our < Latin -ōr- -or2 or -ātōr- -ator
Related forms
controllership, noun Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the web for controller
  • Adjust your irrigation controller to fit your climate conditions and landscaping.
  • But if he's moody and impulsive, tell him to step away from the controller.
  • If you're planning to install an irrigation system or replace an old controller, check out your options.
  • The best way to water vegetables in containers is with drip irrigation operated by an automatic controller.
  • When the antenna signals that the robot is veering too close to a wall, for example, the controller steers the robot away.
  • There, a small controller box generates a high-frequency signal to try and switch off the pain-causing part of the brain.
  • All functions are accessed with a thumb-operated controller and easy-to-navigate, on-screen menus.
  • The engine controller opens the throttle to accelerate the car or closes it to slow the car using engine drag.
  • With an almost desperate gesture, he reaches out for the controller and manages to press the button again.
  • If the pilot turns off the device, the aircraft disappears from the controller's scope.
British Dictionary definitions for controller


a person who directs, regulates, or restrains
Also called comptroller. a business executive or government officer who is responsible for financial planning, control, etc
the equipment concerned with controlling the operation of an electrical device
Derived Forms
controllership, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for controller

late 14c., from Anglo-French contrerolleour (late 13c.), Old French contrerelleor (Modern French contrôleur), from Medieval Latin contrarotulator, agent noun from *contra-rotulare (see control (v.)). Mechanical sense is from 1867.

Online Etymology Dictionary, © 2010 Douglas Harper
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controller in Technology
Part of a computer, typically a separate circuit board, which allows the computer to use certain kinds of peripheral devices. A disk controller is used to connect hard disks and floppy disks, a network controller is used for Ethernet. Other controllers are: keyboard controller, interrupt controller and graphics controller.
The Free On-line Dictionary of Computing, © Denis Howe 2010
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