1. A thin, flat, circular object or plate.
2. The disk used in a disc brake.
3. A disk used on a disk harrow for agricultural purposes.
4. A magnetic disk; such as, a floppy disk or hard disk; the data stored on such a disk: "The instructions suggested that we read the disk that came with the manual."
5. A round, flattened, plate-like structure in an animal; such as, an intervertebral disk.
6. In botany, the enlarged area bearing numerous tiny flowers, as in the flower head of composite plants; such as, the daisy. Also called a discus.
7. In computer science, a magnetic disk; such as, a floppy disk or hard disk.
8. An optical disk, especially a compact disk.
9. A circular grid in a phototypesetting machine.

1. To work (soil) with a disk harrow.
2. To make (a recording) on a phonograph record.

A disk of interstellar material surrounding a celestial object with an intense gravitational field; such as, a black hole.

An electrophoretic technique (migration of electrically charged particles) which separates proteins by their physical interaction with the supporting medium as well as by electrophoretic mobility.

Proteins migrate through layered gels of differing pore size and/or pH, forming discontinuous and concentrated disks of individual molecules within the gel layers.

A rigid magnetic disk mounted permanently in a drive unit of a computer.

1. Rupturing of the tissue that separates the vertebral bones of the spinal column.
2. An intervertebral disk (between two adjacent vertebrae) in which the nucleus pulposus has protruded through the surrounding fibrocartilage, occurring most frequently in the lower lumbar region, and less commonly in the cervical region.

Mild to severe symptoms may result from pressure on spinal nerves; also known as, "a ruptured intervertebral disk", or "a slipped disk" (the action of the nuclear tissue when it is forced from the center of the disc).

The center of the disc, which is called the nucleus, is soft, springy, and receives the shock of standing, walking, running, etc.

The outer ring of the disc, which is called the annulus (Latin for "ring"), provides structure and strength to the disc. The annulus consists of a complex series of interwoven layers of fibrous tissue that hold the nucleus in place.

When the disc has herniated, or ruptured, it may create pressure against one or more of the spinal nerves which can cause pain, weakness, or numbness in the neck and arm. Other names for herniated discs are "prolapsed discs" and "ruptured discs".

1. The circular area in the retina that is the site of the convergence of fibers from the ganglion cells of the retina to form the optic nerve.
2. Otherwise known as the "blind spot" of the eye, the disc is the beginning of the optic nerve; the point where nerve fibers from the retina's rods and cones (the light-sensitive and color-sensitive cells) leave the eyeball.

A grooveless disk on which digital data; such as, text, music, or pictures, is stored as tiny pits in the surface and is read or replayed by a laser beam scanning the surface.

A rotating disk of dust and gas which surrounds the core of a developing solar system.

It may eventually develop into orbiting celestial bodies; such as, planets and asteroids.