potentate vs rani

potentate

noun
  • A powerful leader; a monarch; a ruler. 

  • A self-important person. 

  • A powerful polity or institution. 

  • Someone acting in an important role. 

rani

noun
  • A Hindu princess or female ruler in India. 

  • The wife of a rajah. 

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