Ellipticity

2 definitions found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  Ellipticity \El`lip*tic"i*ty\, n. [Cf. F. ellipticit['e].]
     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 1/29966.


     [1913 Webster]
  
     Note: Some writers use ellipticity as the ratio of the
           difference of the two semiaxes to the minor axis,
           instead of the major. --Nichol.
           [1913 Webster]

From WordNet (r) 2.0 [wn]:

  ellipticity
       n : the property possessed by a rounded shape that is flattened
           at the poles; "the oblateness of the planet" [syn: {oblateness}]