1 a : the quality or state of being eccentric
b : deviation from an established pattern or norm; especially : odd or whimsical behavior
2 a : a mathematical constant that for a given conic section is the ratio of the distances from any point of the conic section to a focus and the corresponding directrix
b : the eccentricity of an astronomical orbit used as a measure of its deviation from circularity
The Laws of Planetary Motion I. The orbits of the planets are ellipses, with the Sun at one focus of the ellipse. II. The line joining the planet to the Sun sweeps out equal areas in equal times as the planet travels around the ellipse. III. The ratio of the squares of the revolutionary …