"Ignition" refers to the process of starting a fire or engine. In the context of engines, it involves the moment when a fuel-air mixture is ignited, leading to combustion that powers the vehicle. This process is crucial for the operation of internal combustion engines found in cars, motorcycles, and other machinery. In a broader sense, "ignition" can also describe the initiation of any process or event. For example, in scientific experiments, ignition might refer to the point at which a chemical reaction begins. Understanding ignition is essential in fields like automotive engineering, fire safety, and chemistry.