downfall vs senescence

downfall

noun
  • The cause of such a fall; a critical blow or error. 

  • A precipitous decline in fortune; death or rapid deterioration, as in status or wealth. 

  • An act of falling down. 

verb
  • To fall down; deteriorate; decline. 

senescence

noun
  • Condition when the cell ceases to divide. 

  • Old age; accumulated damage to macromolecules, cells, tissues and organs with the passage of time. 

  • The state or process of ageing, especially in humans; old age. 

  • Fruit senescence, leading to ripening of fruit. 

  • Ceasing to divide by mitosis because of shortening of telomeres or excessive DNA damage. 

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