area of authority vs specialty

area of authority

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

specialty

noun
  • That in which one specializes; a chosen expertise or talent. 

  • A particular or peculiar case. 

  • An attribute or quality peculiar to a species. 

  • A contract or obligation under seal; a contract by deed; a writing, under seal, given as security for a debt particularly specified. 

  • A product that originates in and is characteristic of a place. 

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