knit cap vs toboggan

knit cap

noun
  • A soft, head-hugging cap usually without a specified front or back, barring those with designs or logos 

toboggan

noun
  • A knit cap, designed to provide warmth in cold weather. 

  • A long sled without runners, with the front end curled upwards, which may be pulled across snow by a cord or used to coast down hills. 

  • Something which, once it starts going (figuratively) downhill, is unstoppable until it reaches the bottom. 

  • A similar sled of wood, pulled by dogs, possibly with steel runners, made to transport cargo. 

verb
  • To go downhill unstoppably until one reaches the bottom. 

  • To slide down a hill on a toboggan or other object. 

  • To fly sharply downward so as to build up speed to facilitate in-flight refueling of a faster aircraft. 

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