Controller

n.	1.	One who, or that which, controls or restraines; one who has power or authority to regulate or control; one who governs. The great controller of our fate Deigned to be man, and lived in low estate. - Dryden.
	2.	An officer appointed to keep a counter register of accounts, or to examine, rectify, or verify accounts.
	3.	(Naut.) 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.	(Elec.) Any electric device for controlling a circuit or system;
	5.	(Mach.) 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.

Noun	1.	controller - someone who maintains and audits business accounts Synonyms: accountant, comptroller
	2.	controller - a person who directs and restrains Synonyms: restrainer
	3.	controller - a mechanism that controls the operation of a machine; "the speed control on his turntable was not working properly"; "I turned the controls over to her" Synonyms: control

(hardware)

controller - 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.

Big Brother, CA, CPA, accountant, accountant general, actuary, auditor, bank accountant, bank examiner, boatswain, bookkeeper, boss, bursar, calculator, cashier, cashkeeper, certified public accountant, chamberlain, chartered accountant, chief, clerk, comptroller, control, cost accountant, cost keeper, curator, depositary, depository, financial officer, floor manager, floorman, floorwalker, foreman, gaffer, ganger, governor, head, headman, inspector, journalizer, liquidator, monitor, noncommissioned officer, overman, overseer, paymaster, proctor, purse bearer, purser, receiver, reckoner, recorder, registrar, regulator, servo control, servo regulator, sirdar, slave driver, steward, straw boss, subforeman, super, superintendent, supervisor, surveyor, taskmaster, treasurer, trustee, visitor