duchy vs lordship

duchy

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

lordship

noun
  • Dominion; power; authority. 

  • The state or condition of being a lord. 

  • Seigniory; domain; the territory over which a lord holds jurisdiction; a manor. 

  • A boy or man who is behaving in a seigneurial manner or acting like a lord, behaving in a bossy manner or lording it up 

  • Title applied to a lord, bishop, judge, or another man with a title. 

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