backlog vs catchment

backlog

noun
  • A reserve source or supply. 

  • A log containing text previously read, as in text-based video games or chat rooms. 

  • A large log to burn at the back of a fire. 

  • An accumulation or buildup, especially of unfilled orders, unconsumed products or unfinished work. 

verb
  • To acquire something as a backlog, or to become a backlog 

catchment

noun
  • A catchment area, or the people it serves. 

  • Any structure or land feature which catches and holds water; the collection of such water. 

verb
  • To divide into catchment areas. 

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