discoidal vs spheric

discoidal

adj
  • Having the flat, circular shape of a disc or a quoit 

spheric

adj
  • Spherical. 

  • Of or relating to the heavenly orbs, or to the sphere or spheres in which, according to ancient astronomy and astrology, they were set. 

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