burden vs heart

burden

noun
  • Theme, core idea. 

  • A phrase or theme that recurs at the end of each verse in a folk song or ballad. 

  • The proportion of ore and flux to fuel, in the charge of a blast furnace. 

  • The capacity of a vessel, or the weight of cargo that she will carry. 

  • A responsibility, onus. 

  • The tops or heads of stream-work which lie over the stream of tin. 

  • A fixed quantity of certain commodities. 

  • The drone of a bagpipe. 

  • A cause of worry; that which is grievous, wearisome, or oppressive. 

  • The total amount of toxins, parasites, cancer cells, plaque or similar present in an organism. 

  • A heavy load. 

verb
  • To impose, as a load or burden; to lay or place as a burden (something heavy or objectionable). 

  • To encumber with a literal or figurative burden. 

heart

noun
  • The centre, essence, or core. 

  • A wight or being. 

  • A muscular organ that pumps blood through the body, traditionally thought to be the seat of emotion. 

  • A playing card of the suit hearts featuring one or more heart-shaped symbols. 

  • Vigorous and efficient activity; power of fertile production; condition of the soil, whether good or bad. 

  • One's feelings and emotions, especially considered as part of one's character. 

  • The twenty-fourth Lenormand card. 

  • The seat of the affections or sensibilities, collectively or separately, as love, hate, joy, grief, courage, etc.; rarely, the seat of the understanding or will; usually in a good sense; personality. 

  • Emotional strength that allows one to continue in difficult situations; courage; spirit; a will to compete. 

  • A conventional shape or symbol used to represent the heart, love, or emotion: ♥ or sometimes <3. 

verb
  • To form a dense cluster of leaves, a heart, especially of lettuce or cabbage. 

  • To fill an interior with rubble, as a wall or a breakwater. 

  • To be fond of. Often bracketed or abbreviated with a heart symbol. 

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