The phrase "ignition cylinder" refers to the part of a vehicle's ignition system where you insert the key to start the engine. It is a cylindrical component that contains the ignition switch, allowing you to turn the car on and off. Full definition
Transmission: 6 - Speed Automatic w / Sportmatic - inc: drive mode select (ECO, Normal, Sport), Remote Keyless Entry, Cruise Control w / Steering - Wheel Mounted Controls, Center Console Armrest, storage, Illuminated Ignition Cylinder Ring (markkia.com)
Bertone and Giugiaro's work of art retained the same lines as the Giulia Sprint GT, with lighter aluminum body panels and a 1600 engine with double ignition cylinder head. (alfaromeousa.com)
Besides the instrument cluster, electrical harness, relays, fuses and ground wires that supply power to the cluster, the only other possibility that I can think of would be a faulty ignition cylinder connection... (yourmechanic.com)