blockhouse vs supply depot

blockhouse

noun
  • A sturdy military fortification, often of concrete, with gunports. 

  • A reinforced building from which to control hazardous operations, such as an explosion or a rocket launch. 

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 blockhouse and supply depot occurred in a corpus of books? (source: Google Ngram Viewer )