Definition of eccentricity
plural eccentricities
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
