foxhole vs warren

foxhole

noun
  • The burrow in the ground where a fox lives. 

  • A small pit dug into the ground as a shelter for protection against enemy fire. 

verb
  • To dig a military foxhole into, or convert into a foxhole by digging. 

  • To drive into a military foxhole. 

warren

noun
  • The system of burrows where rabbits live. 

  • The right to maintain and hunt an area of small beasts, similar to a free warren, but with certain limitations, such as restricting the right to hunt on parts of the land held by freeholders. 

  • A mazelike place of passages and/or rooms in which it's easy to lose oneself; especially one that may be overcrowded. 

  • A place legally authorized for the keeping, breeding and hunting of beasts of warren, especially rabbits. 

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