burghal vs oppidan

burghal

adj
  • Relating to a burgh or borough. 

oppidan

adj
  • Of or pertaining to a town or conurbation. 

noun
  • A class of student in traditional English public schools such as Eton; opposed to colleger or King's Scholar. 

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