country vs duchy

country

noun
  • The territory of a nation, especially an independent nation state or formerly independent nation; a political entity asserting ultimate authority over a geographical area; a sovereign state. 

  • An area of land; a district, region. 

  • A rural area, as opposed to a town or city; the countryside. 

  • The rock through which a vein runs. 

  • A set region of land having particular human occupation or agreed limits, especially inhabited by members of the same race, speakers of the same language etc., or associated with a given person, occupation, species etc. 

adj
  • From or in the countryside or connected with it. 

  • Of or connected to country music. 

  • Originating in India rather than being imported from Europe or elsewhere. 

duchy

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

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