ear lobe vs lobule

ear lobe

noun
  • The lower, exterior, fleshy, bulbous part of the human ear. 

  • The fleshy patch of skin below the ear tuft of a chicken. 

lobule

noun
  • A small lobe; a subdivision of a lobe. 

  • In liverworts with bilobed leaves, the smaller of the two lobes, sometimes modified to form a sac. 

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