mackinaw vs ulster

mackinaw

noun
  • A heavy woolen cloth. 

  • A flat-bottomed cargo boat; mackinaw boat. 

  • A blanket made of wool, formerly distributed to the Amerindians by the U.S. government. 

ulster

noun
  • A long, loose overcoat made of wool or other rough material, often called a greatcoat, which sometimes features an attached shoulder cape covering the back and sleeves, and which can sometimes be buttoned in front. 

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