due vs heliotrope

due

adj
  • On a direct bearing, especially for the four points of the compass 

  • Appropriate. 

  • Owing; ascribable, as to a cause. 

  • Owed or owing. 

  • Scheduled; expected. 

  • Having reached the expected, scheduled, or natural time. 

adv
  • Directly; exactly. 

noun
  • Deserved acknowledgment. 

  • That which is owed; debt; that which belongs or may be claimed as a right; whatever custom, law, or morality requires to be done, duty. 

  • Right; just title or claim. 

  • A membership fee. 

heliotrope

adj
  • Keeping one’s face turned toward the sun. 

  • Light purple or violet. 

noun
  • A light purple or violet colour. 

  • Particularly, a purple-flowered plant of the species Heliotropium arborescens. 

  • A bloodstone (a variety of quartz). 

  • An instrument, employed in triangulation, that uses a mirror to reflect sunlight toward another, very distant, surveyor. 

  • The fragrance of heliotrope flowers. 

  • A plant that turns so that it faces the sun. 

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