fortification vs skyscraper

fortification

noun
  • A jagged pattern sometimes seen during an attack of migraine. 

  • The act of fortifying; the art or science of fortifying places to strengthen defence against an enemy. 

  • That which fortifies; especially, a work or works erected to defend a place against attack; a fortified place; a fortress; a fort; a castle. 

  • An increase in effectiveness, as by adding ingredients. 

skyscraper

noun
  • A very tall building with a large number of floors. 

  • Anything very tall or high. 

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