den vs safe haven

den

noun
  • A squalid or wretched place; a haunt. 

  • Synonym of fort (“structure improvised from furniture, etc. for playing games.”) 

  • A comfortable room not used for formal entertaining. 

  • A group of Cub Scouts of the same age who work on projects together. 

  • A small cavern or hollow place in the side of a hill, or among rocks; especially, a cave used by a wild animal for shelter or concealment. 

verb
  • To ensconce or hide oneself in (or as in) a den. 

safe haven

noun
  • A place of safety or refuge. 

  • An investment that would lose little of its value in the event of a stock market crash. 

  • A financially secure offshore bank or country during times of extreme uncertainty, or when domestic banks are suspected of becoming insolvent. 

  • A protected zone in a country, especially one designated for members of an ethnic or religious minority. 

  • The hours of the day when it is permissible for broadcasting radio stations in the United States to broadcast profanity over radio waves without fear of retribution from the FCC. 

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