Eccentricity is a measure of how much an orbit deviates from being circular. In astronomy, it describes the shape of an orbit around a celestial body, such as a planet or a star. An eccentricity of 0 indicates a perfect circle, while values between 0 and 1 represent elliptical orbits. Higher values indicate more elongated shapes. In mathematics, eccentricity can also refer to the properties of conic sections, such as circles, ellipses, parabolas, and hyperbolas. Each conic section has a specific eccentricity value that helps define its shape. For example, a circle has an eccentricity of 0, while a hyperbola has an eccentricity greater than 1.