"Pushbutton ignition" refers to a system in vehicles where you can start the engine by simply pressing a button instead of using a key. Full definition
The Keyless Access System with Smart Entry ® and pushbutton ignition allows you to walk up to the ILX, unlock the doors and start the engine without ever having to take the key out of your pocket. (acura.com)
The dash, and the whole interior, is blessedly free of gimmicks — save perhaps the keyless pushbutton ignition in the higher - trim model. (automobilemag.com)
The standard Keyless Access System with pushbutton ignition lets you unlock the ILX doors, enter the car and start the engine without ever taking the key from your pocket. (acura.com)