duchess vs rani

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. 

rani

noun
  • A Hindu princess or female ruler in India. 

  • The wife of a rajah. 

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