pileus vs taj

pileus

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

  • 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. 

taj

noun
  • A tall brimless hat, usually conical or curved on top, worn in Muslim countries as a sign of distinction and prestige. 

  • A crown worn by Indian princes as a sign of high rank. 

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