cantonment vs military prison

cantonment

noun
  • A permanent military station. 

  • Temporary military living quarters. 

  • A town or village, or part of a town or village, assigned to a body of troops for quarters. 

military prison

noun
  • A prison operated by the military. 

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