discoid vs discus

discoid

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

adj
  • Shaped like a disc/disk. 

discus

noun
  • A discus fish (genus Symphysodon) 

  • The athletics sport of discus throwing. 

  • A round plate-like object that is thrown for sport. 

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