- A discus; a quoit.
- A flat, circular plate; as, a disk of metal or paper.
- The circular figure of a celestial body, as seen projected of
- A circular structure either in plants or animals; as, a blood
disk; germinal disk, etc.
- The whole surface of a leaf.
- The central part of a radiate compound flower, as in
- A part of the receptacle enlarged or expanded under, or
around, or even on top of, the pistil.
- The anterior surface or oral area of coelenterate animals, as
of sea anemones.
- The lower side of the body of some invertebrates, especially
when used for locomotion, when it is often called a creeping disk.
- In owls, the space around the eyes.