elegiac vs threnodial

elegiac

adj
  • Of or relating to an elegy. 

  • Expressing sorrow or mourning. 

noun
  • A poem composed in the couplet style of classical elegies: a line of dactylic hexameter followed by a line of dactylic pentameter. 

threnodial

adj
  • Pertaining or similar to a threnody. 

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