discoid vs disk

discoid

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

adj
  • Shaped like a disc/disk. 

disk

noun
  • Something resembling a disk. 

  • A disc - either a CD-ROM, an audio CD, a DVD or similar removable storage medium. 

  • A ring- or cup-shaped enlargement of the flower receptacle or ovary that bears nectar or, less commonly, the stamens. 

  • A type of harrow. 

  • A thin, flat, circular plate or similar object. 

  • An intervertebral disc 

verb
  • To harrow. 

  • To move towards, or operate at, zero blade pitch, orienting the propeller blades face-on to the oncoming airstream and maximising the drag generated by the propeller. 

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