improvement vs senescence

improvement

noun
  • Increase; growth; progress; advance. 

  • The act of improving; advancement or growth; a bettering 

  • Something which is improved 

  • Valuable additions or betterments, for example buildings, clearings, drains, fences, etc., on premises. 

  • A useful addition to, or modification of, a machine, manufacture, or composition. 

  • The state of being improved; betterment; advance 

  • The act of making profitable use or application of anything, or the state of being profitably employed; practical application, for example of a doctrine, principle, or theory, stated in a discourse. 

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. 

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