disc
From ZooTerms (Dictionary of Invertebrate Zoology)
disc also disk (noun; Latin discus, circular plate): 1. Any flattened part in the form of a disc.
2. Circumoral area of many animals.
3. (Arthropoda: Insecta) In Coleoptera, the general dorsal surface of the elytra, usually marked by longitudinal striae corresponding to a row of sclerotized pillars connecting the upper and lower faces of the elytra.
4. (Echinodermata: Asteroidea) The central part of the body.
5. (Mollusca: Bivalvia) The whole valve exclusive of the auricles in Pectinacea.
