redoubt vs supply depot

redoubt

noun
  • A small, temporary, military fortification. 

  • A reinforced refuge; a fort. 

  • The return of doubt. 

  • A place of safety or refuge. 

verb
  • To fortify, to make into a stronghold. 

  • To doubt again. 

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