pinna vs promontory

pinna

noun
  • The visible part of the ear that resides outside of the head, the auricle; outer ear excluding the ear canal. 

  • A feather, wing, fin, or other similar appendage. 

  • A leaflet or primary segment of a pinnate compound leaf. 

promontory

noun
  • A rounded elevation in the tympanum of the ear. 

  • A projection on the sacrum. 

  • A high point of land extending into a body of water, headland; cliff. 

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