pinna vs rectrix

pinna

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

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

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

rectrix

noun
  • A flight feather on the tails of birds, used for directional control. 

  • A governess; a rectoress. 

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