inhumation vs threnode

inhumation

noun
  • The act of burial. 

  • arenation 

  • The act of burying vessels in warm earth in order to expose their contents to a steady moderate heat; the state of being thus exposed. 

threnode

noun
  • A threne, or threnody; a dirge; a funeral song. 

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