ignition
n. C / Un. the act of starting a fire or an engine. You use this word when you turn the key in a car to make it start.
n. the process of initiating combustion or the mechanism that starts an internal combustion engine. Often refers to the electrical system that provides the spark for fuel ignition.
He turned the key in the ignition, but the car didn't start.
The pilot checked the fuel levels and the ignition system before attempting to take off.
Engineers are developing a more efficient ignition sequence to reduce the amount of unburned fuel released during the initial combustion phase of the rocket launch.
From French ignition.
Uncountable when referring to the chemical process of starting to burn; countable when referring to the mechanical switch in a vehicle.