bento vs packed lunch

bento

noun
  • A Japanese takeaway lunch served in a box, often with the food arranged into an elaborate design. 

  • A menu icon of nine squares in a grid. 

packed lunch

noun
  • A picnic meal, sandwiches or anything packed and intended to be eaten away from home. 

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