aevum vs eternity

aevum

noun
  • 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. 

eternity

noun
  • Existence outside of time. 

  • Existence without end, infinite time. 

  • A period of time which extends infinitely far into the future. 

  • The remainder of time that elapses after death. 

  • A comparatively long time. 

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