ellipsoid vs oval

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. 

oval

adj
  • Having the shape of an oval. 

  • Of or pertaining to an ovum. 

noun
  • A thing having such a shape, such as an arena. 

  • In a projective plane, a set of points such that no three are collinear and there is a unique tangent line at each point. 

  • An elongated round shape resembling an egg or ellipse. 

  • A sports field, typically but not exclusively oval in shape. 

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