packing case vs pyxis

packing case

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

pyxis

noun
  • A small box 

  • A nautical compass 

  • A capsule in which the lid separates from the top of the fruit to release the seeds; a pyxidium 

  • The box in which ashes are stored for Ash Wednesday 

  • acetabulum 

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