Disk shell

Disk Disk (d[i^]sk), n. [L. discus, Gr. di`skos. See {Dish}.] [Written also {disc}.] 1. A discus; a quoit. [1913 Webster]

Some whirl the disk, and some the javelin dart. --Pope. [1913 Webster]

2. A flat, circular plate; as, a disk of metal or paper. [1913 Webster]

3. (Astron.) The circular figure of a celestial body, as seen projected of the heavens. [1913 Webster]

4. (Biol.) A circular structure either in plants or animals; as, a blood disk; germinal disk, etc. [1913 Webster]

5. (Bot.) (a) The whole surface of a leaf. (b) The central part of a radiate compound flower, as in sunflower. (c) A part of the receptacle enlarged or expanded under, or around, or even on top of, the pistil. [1913 Webster]

6. (Zo["o]l.) (a) The anterior surface or oral area of c[oe]lenterate animals, as of sea anemones. (b) The lower side of the body of some invertebrates, especially when used for locomotion, when it is often called a creeping disk. (c) In owls, the space around the eyes. [1913 Webster]

{Disk engine}, a form of rotary steam engine.

{Disk shell} (Zo["o]l.), any species of Discina. [1913 Webster]