dropbox vs packing case

dropbox

noun
  • A box wherein objects can be deposited by one person for later collection by another. 

  • A computer folder to which files may be dragged and dropped and from which users of other computers on the network can access those files. 

  • An enhancement to a loom that allows patterns of multiple colors to be woven from the same loom. 

packing case

noun
  • A large, sturdy box or wooden crate used for the secure shipment of goods. 

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