If you mean as in the cartilage between the bones in the spine - it's 'disc'
"Disk" is Spanish is "el disco".
how to spell
A field spell
The medical problems that can be fixed by a cervical disk surgery are all back problems such as rupturing a disk in one's back which can cause the need for surgery.
medical crew
That sentence makes no sense, but, "Give you that disk, please."
it can spell piperacillin, an antibiotic
The acronym 'CD', often refers to 'compact disk'.
sense as in common sense or a sense of style or the five senses
The word disk, as it applies to the back, refers to elastic tissue that sits between the vertebrae. These disks absorb shock during movement.
Herniated Nucleus Pulposus (HNP) - medical terminology for the following: Lumbar radiculopathy; Cervical radiculopathy; Herniated intervertebral disk; Prolapsed intervertebral disk; Slipped disk; Ruptured disk A herniated nucleus pulposus is a slipped disk along the spinal cord. The condition occurs when all or part of the soft center of a spinal disk is forced through a weakened part of the disk. definition comes from the Univ. of Maryland Medical Center web site.
I sense you're talking about the infinite disk, the hyperbolic disk or the Poincare disk. The limit of the circumference is infinite and a real number and is not actually part of the hyperbolic plane.