enthrallment vs entombment

enthrallment

noun
  • The act of enthralling or the state of being enthralled 

entombment

noun
  • The act of entombing or the state of being entombed 

  • The decommissioning of a radioactive site by encasing it in concrete 

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