ellipsoid vs ovaliform

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. 

ovaliform

adj
  • Shaped like an egg; having a figure such that any section in the direction of the shorter diameter will be circular, and any in the direction of the longer diameter will be oval. 

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