What does it mean to have cervical spinal stenosis?

Narrowing. Stenosis can be central, narrowing of the canal formed by the bony arch of the vertebrae that the spinal cord hangs in. Or it can be narrowing of the openings to the sides that the spinal nerves exit between the vertebrae. This can be caused by hypertrophy or thickening of the bony parts or the ligament along the back of the vertebral bodies or the discs pushing into the spaces or a combination.
Narrowed spine canal. In the neck or cervical region, the spinal canal is too narrow causing neural tissue compression of either the spinal cord or nerves or both caused by a canal or foramen that started too small or narrowed with age due to degeneration or as result of other conditions that affect the spine leading to this narrowing with neural compression. Sometimes there are no symptoms, just a finding on studies.