floccule vs flocculus

floccule

noun
  • A small, loosely aggregated mass of material suspended in, or precipitated from a solution; a floc. 

flocculus

noun
  • A small fluffy tuft. 

  • A marking on the surface of the sun associated with a solar prominence. 

  • Either of two small lobes on the posterior border of the cerebellum. 

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