duchess vs marquess

duchess

noun
  • The female ruler of a duchy. 

  • The wife or widow of a duke. 

verb
  • to court or curry favour for political or business advantage; to flatter obsequiously. 

marquess

noun
  • A title of nobility for a man ranking beneath a duke and above an earl. 

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