catacomb vs charnel

catacomb

noun
  • An underground system of tunnels and chambers with recesses for graves, used (in former times) as a cemetery; a tunnel system used for burying the dead, as in Paris or Ancient Rome. 

charnel

noun
  • A chapel attached to a mortuary. 

  • Part of a helm, now usually identified as the hinge (near the neck) by which the helm was secured to the breastplate. 

  • A repository for dead bodies. 

adj
  • Of or relating to a charnel, deathlike, sepulchral. 

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