down feather vs fin

down feather

noun
  • A feather of the down of a bird 

fin

noun
  • A hairstyle, resembling the fin of a fish, in which the hair is combed and set into a vertical ridge along the top of the head from about the crown to the forehead. 

  • A similar structure on the tail of a bomb, used to help keep it on course. 

  • The conning tower of a submarine. 

  • a five-pound (£5) note; the sum of five pounds. 

  • One of the appendages of a fish, used to propel itself and to manoeuvre/maneuver. 

  • An extending part on a surface of a radiator, engine, heatsink, etc., used to facilitate cooling. 

  • A sharp raised edge (generally in concrete) capable of damaging a roof membrane or vapor retarder. 

  • A device worn by divers and swimmers on their feet. 

  • The finish, the end 

  • A similar appendage of a cetacean or other marine animal. 

  • A thin, rigid component of an aircraft, extending from the fuselage and used to stabilise and steer the aircraft. 

verb
  • To cut the fins from a fish, shark, etc. 

  • (Of a fish) to swim with the dorsal fin above the surface of the water. 

  • To swim in the manner of a fish. 

  • To provide (a motor vehicle etc) with fins. 

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