senescence vs youth

senescence

noun
  • 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. 

  • Condition when the cell ceases to divide. 

youth

noun
  • A young man; a male adolescent or young adult. 

  • The quality or state of being young. 

  • The part of life following childhood; the period of existence preceding maturity or age; the whole early part of life, from childhood, or, sometimes, from infancy, to adulthood. 

  • A young person. 

  • Young persons, collectively. 

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