epoch vs reign

epoch

noun
  • A notable event which marks the beginning of such a period. 

  • A geochronologic unit of hundreds of thousands to millions of years; a subdivision of a period, and subdivided into ages (or sometimes subepochs). 

  • A specific instant in time, chosen as the point of reference or zero value of a system that involves identifying instants of time. 

  • A particular period of history, or of a person's life, especially one considered noteworthy or remarkable. 

  • One complete presentation of the training data set to an iterative machine learning algorithm. 

verb
  • To divide (data) into segments by time period. 

reign

noun
  • The period during which a monarch rules. 

  • The exercise of sovereign power. 

  • The territory or sphere over which a kingdom; empire; realm; dominion, etc. is ruled. 

verb
  • To exercise sovereign power, to rule as a monarch. 

  • To reign over (a country) 

  • To be a dominant quality of a place or situation; to prevail, predominate, rule. 

  • To be the winner of the most recent iteration of a competition. 

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