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