discoid vs pellicle

discoid

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

adj
  • Shaped like a disc/disk. 

pellicle

noun
  • A thin plastic membrane used as a beam splitter or protective cover. 

  • A skin or coating of proteins on the surface of meat to be smoked, improving the surface adhesion. 

  • The growth on the surface of a liquid culture. 

  • The skin of a mushroom cap. 

  • A thin skin or film. 

  • The outermost layer of a mushroom, often used only for a surface that is viscid and easily peels off. 

  • Cuticle, the hard protective outer layer of certain life forms. 

  • The photosensitive emulsion of photographic film. 

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