circular vs spheric

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. 

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 circular and spheric occurred in a corpus of books? (source: Google Ngram Viewer )