Definition: A disc (plural: discs). A disc, in a mathematical sense, is an abstract representation or model for a physical object, such as a cone or sphere. In physics, it represents a set of physical quantities that are to be measured or observed. In mathematics, it can refer to any type of structure that has the ability to represent and manipulate various types of data or information. In its broader sense, a disc is a geometric figure used for representing mathematical concepts like angles or lines, as well as in music theory. The term "disc" was historically used to denote a musical instrument, such as a harmonium or harp. A disc can be made from a variety of materials, including metals (e.g., aluminum discs), plastics (e.g., rubber, plastic, vinyl), and paper (e.g., cardboard). Discs are commonly used in sound systems and other audio applications. The term "disc" is also used as an adjective to describe any object that has the ability or capability for representing a complex mathematical operation. For example: • A disc of metal can represent a function whose output depends on its input.