heading vs knockdown

heading

noun
  • The direction into which a seagoing or airborne vessel's bow is pointing (apparent heading) and/or the direction into which it is actually moving relative to the ground (true heading) 

  • The end of a stone or brick which is presented outward. 

  • A strip of material at the hoist end of a flag, used for attaching the flag to its halyard. 

  • The title or topic of a document, article, chapter, or of a section thereof. 

  • Material for the heads of casks, barrels, etc. 

  • A gallery, drift, or adit in a mine; also, the end of a drift or gallery; the vein above a drift. 

  • The extension of a line ruffling above the line of stitch. 

knockdown

noun
  • The condition of a sailboat being pushed abruptly to horizontal, with the mast parallel to the water surface. 

  • An act of knocking down or the condition of being knocked down. 

  • A shelter erected for use as a temporary dressing room. 

  • A collection of parts required to assemble a product, typically manufactured in one region and exported elsewhere for assembly. 

  • a short pass played downwards, for example from the head onto someone's feet. 

  • A genetically modified organism that carries one or more genes in its chromosomes that have been made less active or had their expression reduced. 

  • The use of a reagent such as an oligonucleotide with sequence complementary to an active gene or its mRNA transcript, to interfere with the expression of said gene. 

  • An overwhelming blow. 

adj
  • To be formed into a head by upsetting in fastening. 

  • reduced in price, originally to a price below which an article would not be sold by the auctioneer 

  • powerful enough to overwhelm or knock down 

  • Capable of being taken apart for packing or removal. 

verb
  • To employ the knockdown technique 

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