A kill switch, every doomsday machine has one, I guess. It's the last resort off button, and a huge plot device. Robot going crazy? Kill switch. Inator foiled by a teal platypus? Kill switch. Machine gains sentience and greatly dislikes it? Kill switch. It's that easy!
"Bro, help! My vacuum is turning on me and becoming evil!"
"Does it have a killswitch?"
"Uh... no?"
"It was nice knowing you."
noun. A device by which a high-voltage switches and breakers can be flipped using a corded remote from a marked distance away instead of directly manipulating the switch. Clothing can also be used by the switch operator, but "higher powers" (like your boss) insist on keeping people out of the line of fire. Also known as a remote actuation device.
That breaker has 2,000 volts? We're going to need a chickenswitch to flip that; I don't want to get cooked.