Controller
Controller may refer to:

Occupations
Controller or financial controller, or in government accounting comptroller, a senior accounting position
Controller, someone who performs agent handling in espionage
Air traffic controller, a person who directs aircraft

Computing and electronics
Model–view–controller, an architectural pattern used in software engineering
Controller (computing) (disambiguation)
Microcontroller, a small computer on a single integrated circuit
Game controller, an input device used for playing video games

Control engineering
Control theory, control of continuously operating dynamical systems in engineered processes and machines
Irrigation controller, a device to automate irrigation systems
PID controller, a control loop feedback mechanism
Control loop, contains all the control elements for controlling a process variable
Anti-lock brake controller, in an anti-lock braking system
Industrial control system, a general term used in industrial process control
Proportional control, a type of linear feedback control system

Biomedical
Elite controllers, individuals who do not develop AIDS after exposure to HIV

Fiction
Controller (comics), multiple characters
Controller (Marvel Comics), a fictional character in Marvel Comics
Controllers (DC Comics), a fictional extraterrestrial race in the DC Universe
The Fat Controller (Sir Topham Hatt), the head of the railway in The Railway Series of books written by the Reverend W.V. Awdry, also The Thin Controller and The Small Controller on other railway lines in those books
Controller, a being controlled by a Yeerk in the Animorphs series by K.A. Applegate
The Controller, an AI system in the Armored Core 3 video game

Music
Controller (Misery Signals album), 2008
Controller (British India album), 2013
The Controllers (R&B band), a 1980s rhythm-and-blues band
MIDI controller, device which allows people or machines to control multiple aspects of audiovisual performances with MIDI messages
"Controller" (song), a 2017 song by New Zealand L.A.B.
"Controller", a song from the 1981 album Only a Lad by the new-wave band Oingo Boingo
"The Controller", a nickname of musician Nick Rhodes.

See also
Control (disambiguation)
Control unit (disambiguation)
"Controlla", 2016 single by Drake