area of authority vs realm

area of authority

noun
  • the extent of someone's expertise, authority, activity or knowledge 

realm

noun
  • An abstract sphere of influence, real or imagined. 

  • A taxonomic rank in the phylogeny of viruses, higher than kingdoms. 

  • A scope of operation in networking or security. 

  • An otherworldly dimension or domain — magical, ethereal, or otherwise — usually ruled or created by a mystical character. 

  • A territory or state, as ruled by a specific power, especially by a king. 

  • The domain of a certain abstraction. 

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