madam vs queen mother

madam

noun
  • The mistress of a household. 

  • A woman who runs a brothel, particularly one that specializes in finding prostitutes for rich and important clients. 

  • A polite form of address for a woman or lady. 

  • A conceited or quarrelsome girl. 

  • An irritable, conceited, or contemptous woman. (used as a general term of abuse). 

verb
  • To address as "madam". 

queen mother

noun
  • A widowed queen consort (a queen dowager) whose son or daughter from that marriage is the reigning monarch. 

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