aged vs senescent

aged

adj
  • Old. 

  • Having the age of. 

  • Having undergone the improving effects of time; matured. 

noun
  • Old people, collectively. 

senescent

adj
  • Characteristic of old age. 

  • That ceases to divide. 

  • Growing old; decaying with the lapse of time. 

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