Polish vs pileus

Polish

noun
  • A breed of chickens with a large crest of feathers. 

  • The language spoken in Poland. 

adj
  • Of, from or native to Poland, or relating to the Polish language. 

pileus

noun
  • A small thin cloud attached to a cumulus cloud. 

  • The bell of a jellyfish. 

  • The top of the head of a bird, from the bill to the nape. 

  • The cap of a mushroom. 

  • A conical felt hat worn in Ancient Rome and Greece. 

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