circular vs discoid

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. 

discoid

adj
  • Shaped like a disc/disk. 

noun
  • A disk-shaped dental excavator designed to remove the carious dentin of a decayed tooth 

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