the property possessed by a round shape that is flattened at the poles
同义词：oblateness
ellipticity详细解释
el.lip.tic.i.ty
n.（名词） Deviation from perfect circular or spherical form toward elliptic or ellipsoidal form. 椭圆形，椭圆球：从正圆或球形向椭圆或椭圆球的偏离 The degree of this deviation. 椭圆率：指这种偏离的程度
