flash drive vs memory card

flash drive

noun
  • A small electronic device used to store digital data, more portable and robust than a hard drive. 

memory card

noun
  • A solid state digital memory storage format, commonly found on computers, digital cameras and cellphones. 

  • A personal computer's expansion memory module that fits in a standard interface such as a PCI or ISA slot. 

How often have the words flash drive and memory card occurred in a corpus of books? (source: Google Ngram Viewer )