elegiac vs melancholy

elegiac

adj
  • Expressing sorrow or mourning. 

  • Of or relating to an elegy. 

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

melancholy

adj
  • Affected with great sadness or depression. 

noun
  • Great sadness or depression, especially of a thoughtful or introspective nature. 

  • Black bile, formerly thought to be one of the four "cardinal humours" of animal bodies. 

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