assurance vs authority

assurance

noun
  • The state of being assured; total confidence or trust; a lack of doubt; certainty. 

  • Subjective certainty of one's salvation. 

  • The act of assuring; a declaration tending to inspire full confidence; something designed to give confidence. 

  • Firmness of mind; undoubting steadiness; intrepidity; courage; confidence; self-reliance. 

  • Insurance; a contract for the payment of a sum on occasion of a certain event, as loss or death. Assurance is used in relation to life contingencies, and insurance in relation to other contingencies. It is called temporary assurance, in the time within which the contingent event must happen is limited. 

  • Excessive boldness; impudence; audacity 

  • Any written or other legal evidence of the conveyance of property; a conveyance; a deed. 

authority

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

  • 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. 

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

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