A cylinder also refers to the aggregate of all tracks that reside in the same location on every disk surface. On multiple-platter disks, the cylinder is the sum total of every track with the same track number on every surface.
When data is being stored on the system, the operating system fills an entire cylinder, before moving on to the next one. The access arm remains stationary until the process of reading or writing is completed.
Example of usage – “A cylinder is two corresponding tracks on a fixed disk.”