aby vs fall on

aby

verb
  • To endure or tolerate (something); to experience. 

fall on

verb
  • To experience; to suffer; to fall upon. 

  • To be assigned to; to acquire a new responsibility, duty or burden. 

  • To occur on a particular day. 

  • Of the eyes or gaze: to alight upon. 

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