packsack vs pannier

packsack

noun
  • A backpack, knapsack, rucksack or similar bag packed with provisions or personal items, especially as carried by a traveller or a hiker, and often slung over the shoulder. 

pannier

noun
  • A large basket or bag fastened, usually in pairs, to the back of a bicycle or pack animal, or carried in pairs over the shoulders. 

  • One of a pair of hoops used to expand the volume of a woman's skirt to either side. 

  • A breadbasket. 

  • A piece of basketwork for protecting archers, or, filled with gravel or sand, for forming and protecting embankments, etc. 

  • A decorative basket for the display of flowers or fruits. 

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