An ignition key is a small metal device used to start a vehicle's engine. It typically fits into the ignition lock, allowing the driver to turn the ignition system on and off. When the key is turned, it activates the electrical systems necessary for the engine to start running. Modern vehicles often use a smart key or key fob instead of a traditional ignition key. These advanced systems allow for keyless entry and ignition, enhancing convenience and security. The ignition key or its modern alternatives are essential for operating vehicles like cars and motorcycles, ensuring that only authorized users can start the engine.