assignee vs backup

assignee

noun
  • one to whom a thing is assigned 

  • one to whom rights or property is being transferred 

  • one who is appointed to act or speak in place of another; an agent 

backup

noun
  • A reserve or substitute. 

  • reinforcements 

  • A copy of a file or record, stored separately from the original, that can be used to recover the original if it is destroyed or damaged. 

  • An accumulation of material caused by a (partial) obstruction or (complete) blockage of the flow or movement of the material, or an accumulation of material that causes an overflow due to the flow being greater than the maximum possible flow. 

adj
  • Supporting, reinforcing; (music) of or related to accompaniment 

  • Standby, reserve or extra. 

  • That is intended as a backup. 

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