firman vs requirement

firman

noun
  • A royal decree issued by a sovereign in certain historical Islamic states, especially by the Sultan of Turkey. 

requirement

noun
  • Something asked. 

  • A necessity or prerequisite; something required or obligatory. Its adpositions are generally of in relation to who or what has given it, on in relation to whom or what it is given to, and for in relation to what is required. 

  • A statement (in domain specific terms) which specifies a verifiable constraint on an implementation that it shall undeniably meet or (a) be deemed unacceptable, or (b) result in implementation failure, or (c) result in system failure. 

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