circular vs ellipsoid

circular

adj
  • In the shape of, or moving in a circle. 

  • Referring back to itself, so as to prevent computation or comprehension; infinitely recursive. 

  • Circuitous or roundabout. 

  • Of or relating to a circle. 

  • Distributed to a large number of persons. 

noun
  • Synonym of flyer: a printed advertisement, directive, or notice intended for mass circulation. 

  • A shuttle bus with a circular route. 

verb
  • To extend in a circular direction. 

  • To distribute circulars to or at. 

ellipsoid

adj
  • Shaped like an ellipse; elliptical. 

  • Having the tridimensional shape of an ellipse rotated on its long axis. 

  • Of or pertaining to an ellipse; elliptic. 

noun
  • A surface, all of whose cross sections are elliptic or circular (including the sphere), that generalises the ellipse and in Cartesian coordinates (x, y, z) is a quadric with equation x²/a² + y²/b² + z²/c² = 1. 

  • Such a surface used as a model of the shape of the earth. 

How often have the words circular and ellipsoid occurred in a corpus of books? (source: Google Ngram Viewer )