aeviternity vs sempiternity

aeviternity

noun
  • Synonym of eternity (“existence without end”) 

  • Synonym of aevum (“the temporal mode of existence between time and eternity, said to be experienced by angels, saints, and celestial bodies (which medieval astronomy believed to be unchanging)”) 

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 aeviternity and sempiternity occurred in a corpus of books? (source: Google Ngram Viewer )