ETYM Latin discus, Greek diskos. Related to Dish.
1. A thin flat circular plate; SYN. disc.
2. Something with a round shape like a flat circular plate; SYN. disc, saucer.

(Computers) An electronic storage medium which may either be built into a computer (a hard disk), or may be a removable medium (a floppy disk, etc.); SYN. hard disk, floppy disk.
1. A round, flat piece of flexible plastic coated with a magnetic material that can be electrically influenced to hold information recorded in digital (binary) form and encased in a protective plastic jacket to protect the disk from damage and contamination. Also called: floppy, floppy disk, microfloppy disk. Compare compact disc, disc.
2. See hard drive.
In computing, a common medium for storing large volumes of data (an alternative is magnetic tape.) A magnetic disk is rotated at high speed in a disk-drive unit as a read/write (playback or record) head passes over its surfaces to record or “read” the magnetic variations that encode the data. There are several types, including floppy discs, hard discs, and CD-ROM.
Fixed disks provide the most storage. Up to 600 megabytes (million bytes) is quite common, although the hard disks of this type used with microcomputers may hold only 10 or 20 megabytes. Fixed or hard disks are built into the drive unit, occasionally stacked one on top of another. Removable disks are common in minicomputer systems, hold about 80 megabytes of data, and are contained in a rigid plastic case that can be taken out of the drive unit. A floppy disk (also called diskette) is very much smaller in size and capacity. Normally holding less than 1 megabyte of data, it is flexible, mounted in a card envelope or rigid plastic case, and can be removed from the drive unit. Recently, laser disks and compact disks have been used to store computer data. These have an enormous capacity (about 600 megabytes on a compact disk and billions of bytes on a laser disk) but, once written onto the disk, data cannot be erased.

To cultivate with an implement (as a harrow or plow) that turns and loosens the soil with a series of discs.