A GM ignition cylinder is an automotive component designed to accept an ignition key. To start a car, drivers insert the car's ignition key into this cylinder, which turns on a switch to the car's battery.
The ignition cylinder is a small tube that is mechanically turned by the car's driver by inserting a key into it and twisting it to the left or right. The cylinder contains anti-theft protection so that arbitrary keys or other objects cannot be used to turn it.
General Motors, a car manufacturer, has had multiple problems with some of its vehicles' ignition cylinders. In 2014, the company was forced to issue a safety recall on cylinders in several models, including the Pontiac Solstice and Chevrolet Cobalt.
In the models involved in the recall, bumping the keys while the car is in operation can cause the ignition cylinder to twist into the "off" position. This makes the car lose power. Ignition cylinder issues have been implicated in multiple accidents involving these models.