Ellipticity /(?)/

El·lip·tic·i·ty

Ellipticity

n.
  1. Deviation of an ellipse or a spheroid from the form of a circle or a sphere; especially, in reference to the figure of the earth, the difference between the equatorial and polar semidiameters, divided by the equatorial; thus, the ellipticity of the earth is <frac:1_29966/.