crossbow vs fascine knife

crossbow

noun
  • A mechanised weapon, based on the bow and arrow, that shoots bolts. 

  • A portable ballista that can be held in the hand. 

fascine knife

noun
  • A large, heavy knife or short sword used as a sidearm and tool by 17th to 19th century infantry and artillery. 

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