cartridge vs pencil case

cartridge

noun
  • A vessel which contains the ink or toner for a computer printer and can be easily replaced with another. 

  • The package consisting of the bullet, primer, and casing containing gunpowder; a round of ammunition. 

  • A removable enclosure containing read-only memory devices, used for rapid loading of software onto a home computer or video game console. 

  • A prefabricated subassembly that can be easily installed in or removed from a larger mechanism or replaced with another interchangeable subassembly. 

  • Magnetic tape storage, used for storing (backup) copies of data. 

pencil case

noun
  • An object purposed to contain different stationery like pencil, rubber, correction fluid, etc. 

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