noun the state of being eccentric; deviation from the customary line of conduct; oddity.
2. eccentricity ·noun the distance of the center of figure of a body, as of an eccentric, from an axis about which it turns; the throw.
3. eccentricity ·noun the ratio of the distance between the center and the focus of an ellipse or hyperbola to its semi-transverse axis.
4. eccentricity ·noun the ratio of the distance of the center of the orbit of a heavenly body from the center of the body round which it revolves to the semi-transverse axis of the orbit.