dominion vs duchy

dominion

noun
  • A kingdom, nation, or other sphere of influence; governed territory. 

  • Power or the use of power; sovereignty over something; stewardship, supremacy. 

  • predominance; ascendancy 

  • kingdom 

  • An order of angel in Christian angelology, ranked above virtues and below thrones. 

duchy

noun
  • A dominion or region ruled by a duke or duchess. 

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