centuplet vs millennium

centuplet

noun
  • Synonym of hundred: A group of 100. 

  • One of a group of 100, particularly one of 100 babies born at the same time, from the same egg, or from the same DNA. 

millennium

noun
  • The year in which one period of one thousand years ends and another begins, especially the year 2000. 

  • A period of time consisting of one thousand years. 

  • A period of universal happiness, peace or prosperity; a utopia. 

  • The period of one thousand years during which Christ will reign on earth (according to Millenarianist interpretations). 

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