authority vs mastery

authority

noun
  • Power or right to make or enforce rules or give orders; or a position having such power or right. 

  • A reliable, definitive source of information on a subject. 

  • Persons, regarded collectively, who occupy official positions of power; police or law enforcement. 

  • Official permission; authorisation to act in some capacity on behalf of a ruling entity. 

  • A government-owned agency that runs a revenue-generating activity for public benefit. 

  • Status as a trustworthy source of information, reputation for mastery or expertise; or claim to such status or reputation. 

mastery

noun
  • The position or authority of a master; dominion; command; supremacy; superiority. 

  • Superiority in war or competition; victory; triumph; preeminence. 

  • The act or process of mastering; the state of having mastered; expertise. 

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