ellipsoid of revolution vs spheroidal

ellipsoid of revolution

noun

  • A spheroid; a solid of revolution generated by rotating an ellipse about one of its axes. 

spheroidal

noun

  • A spheroid 

adj

  • Like a spheroid; roughly spherical. 

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