disk also disc 
(dĭsk)
(dĭsk)n.
1. A thin, flat, circular object or plate.
2. Something resembling such an object: The moon's disk was reflected in the pond.
3.
a. The disk used in a disc brake.
b. A disk used on a disk harrow.
4. A round, flattened structure in a plant or animal, such as an intervertebral disk.
5. Botany The central area bearing numerous disk flowers in the flower head of a composite plant such as a daisy.
6. Computers
a. An optical disc, especially a compact disc.
b. A magnetic disk, such as a floppy disk or hard disk.
c. The data stored on such objects.
7. A phonograph record.
8. A circular grid in a phototypesetting machine.
tr.v. disked, disk·ing, disks also disced or disc·ing or discs
1. To work (soil) with a disk harrow.
2. To make (a recording) on a phonograph record.
[Latin discus, quoit, from Greek diskos, from dikein, to throw; see deik- in the Appendix of Indo-European roots.]