effacement vs offloading

effacement

noun
  • The act of expunging, of wiping out; expungement. 

  • A shortening, or thinning, of the cervix before or during early labour. 

  • Withdrawal in order to make oneself inconspicuous; the making of oneself inconspicuous. 

offloading

noun
  • The act by which something is offloaded. 

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