discoid vs hob

discoid

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

adj
  • Shaped like a disc/disk. 

hob

noun
  • A kind of cutting tool, used to cut the teeth of a gear. 

  • A rounded peg used as a target in several games, especially in quoits. 

  • A male ferret. 

  • The top cooking surface on a cooker; a cooktop. It typically comprises several cooking elements (often four), also known as 'rings'. 

  • The flat projection or iron shelf at the side of a fire grate, where things are put to be kept warm. 

  • The hub of a wheel. 

verb
  • To engage in the process of cutting gears with a hob. 

  • To create (a gear) by cutting with a hob. 

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