fastness vs fort

fastness

noun
  • A fortified or secure place; a fortress, a stronghold. 

  • The ability of a dye to withstand fading. 

  • The quality or state of moving quickly; quickness, rapidity, swiftness. 

  • Something used to fasten or tie; a fastener or fastening. 

  • The quality or state of being strongly attached; firmness, secureness, tenacity. 

  • The quality or state of having an extravagant lifestyle or immoral habits. 

fort

noun
  • A fortified defensive structure stationed with troops. 

  • Any permanent army post. 

  • An outlying trading-station, as in British North America. 

  • A structure improvised from furniture, bedding, etc., for playing games. 

verb
  • To create a fort, fortifications, a strong point, or a redoubt. 

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