atemporality vs sempiternity

atemporality

noun
  • The quality of being atemporal. 

sempiternity

noun
  • Eternity; a seemingly everlasting period of time. 

  • Existence within time but infinitely into the future, as opposed to eternity, understood as existence outside time. 

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