cognizance vs enlightening

cognizance

noun
  • An emblem, badge or device, used as a distinguishing mark by the body of retainers of a royal or noble house. 

  • Notice or awareness. 

  • Jurisdiction. 

enlightening

adj
  • Serving to enlighten. 

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