gentry vs main line

gentry

noun
  • People of education and good breeding. 

  • Courtesy; civility; complaisance. 

  • In a restricted sense, those people between the nobility and the yeomanry. 

  • Birth; condition; rank by birth. 

main line

noun
  • A standard sequence of opening moves considered to be best play. 

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