auricle vs pinnule

auricle

noun
  • Any appendage in the shape of an ear or earlobe. 

  • Synonym of atrium. 

  • The outer ear or pinna. 

  • An anterior ear-shaped appendage of the left or right atrium of the human heart. 

pinnule

noun
  • A part or an organ which resembles the barb of a feather, particularly the side branches on the stalks of crinoids; Any of the lateral divisions of the finger-like stalks of an encrinite. 

  • Any of the ultimate leaflets of a bipinnate or tripinnate leaf; a subleaflet. 

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