packsack vs portmanteau

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. 

portmanteau

noun
  • A large travelling case usually made of leather, and opening into two equal sections. 

  • A portmanteau word. 

  • A portmanteau film. 

verb
  • To make a portmanteau word. 

adj
  • Made by combining two (or more) words, stories, etc., in the manner of a linguistic portmanteau. 

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