controller

UK: /kənˈtrəʊlə^r/ US: /kənˈtroʊlɚ/ ,(kən trō′lər)

WordReference Random House Learner's Dictionary of American English © 2026

con•trol•ler /kənˈtroʊlɚ/   n. [countable]

1. Business a government official or an officer of a business firm in charge of financial accounts and transactions;
   comptroller:
   The state controller decided that contributions to the pension fund would stop.
2. a person who regulates or restrains.
3. Mechanical Engineering a regulating mechanism;
   governor.

con•trol•ler•ship, n. [uncountable]

WordReference Random House Unabridged Dictionary of American English © 2026

con•trol•ler  (kən trō′lər), n. 

1. Business an employee, often an officer, of a business firm who checks expenditures, finances, etc.;
   comptroller.
2. a person who regulates, directs, or restrains.
3. [Brit. Aeron.] a dispatcher.
4. a regulating mechanism;
   governor.
5. Computing Also called control unit, processor. 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.

• Latin -ōr- -or² or -ātōr- -ator
• Anglo-French countrero(u)llour, Middle French contrerolleur, equivalent. to contrerolle duplicate roll (see control) + -eur, -our
• Middle English countrollour 1350–1400

con•trol′ler•ship′, n. 

Collins Concise English Dictionary © HarperCollins Publishers::

controller / kənˈtrəʊlə/ noun

1. a person who directs, regulates, or restrains
2. Also called: comptroller a business executive or government officer who is responsible for financial planning, control, etc
3. the equipment concerned with controlling the operation of an electrical device

conˈtrollerˌship noun