turban vs woolly hat

turban

noun
  • A man's headdress made by winding a length of cloth round the head. 

  • A woman's close-fitting hat with little or no brim. 

  • The complete set of whorls of a spiral shell. 

woolly hat

noun
  • an item of knitted headwear, without a brim or peak, made from wool or other fabrics. 

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