Reactor

• Bioreactor, is a device which controls biologically active environment.
• Chemical reactor, a device for containing and controlling a chemical reaction
• Fusion reactor, a device for containing and controlling a fusion power reaction
• An inductor (possessing reactance) in an electrical power grid
  • A current limiting reactor is used to limit starting current of motors and to protect variable frequency drives
• Nuclear reactor, a device for containing and controlling a nuclear reaction
• Reactor (Havok), a physics simulation engine
• The reactor pattern, a design pattern used in concurrent programming

In entertainment

• Reactor an alternative title for the 1978 Italian film War of the Robots directed by Alfonso Brescia
• Re-ac-tor, a 1981 album by Neil Young and Crazy Horse
• Reactor (arcade game), an arcade game created by Gottlieb
• Reactor, Inc., a defunct interactive entertainment company founded by Mike Saenz
• Reactor, a comedy series on Syfy, hosted by David Huntsberger.