From the Latin noun ignis, meaning "fire," the word ignition means "the action of setting something on fire or causing it to burn." During a rocket launch, the ignition that takes place at the end of the countdown lights the rocket's engines afire. In an internal combustion engine, the kind found in many automobiles, the ignition begins the process of combustion of the fuel in the cylinders, driving the pistons, which in turn propels the car forward.