oppidan vs urban

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. 

urban

adj
  • Related to the (or any) city. 

  • Characteristic of city life. 

  • (of inhabitants or residents) Black; African American. 

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