stockade vs supply depot

stockade

noun
  • a military prison 

  • an enclosure protected by a wall of wooden posts 

verb
  • To enclose in a stockade. 

supply depot

noun
  • A facility utilized by armies to store battlefield supplies temporarily on or near the front lines until they can be distributed to army units. 

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