backflash vs throwback

backflash

noun
  • Synonym of flashback (“dramatic device”) 

  • The hazardous situation where the flame propagates backward down the hose of an oxyfuel welding and cutting system. 

throwback

noun
  • A person or thing that evokes memories. 

  • A reversion to an earlier stage of development. 

  • An atavism. 

  • An organism that has characteristics of a more primitive form. 

  • Coordinate terms: nowhere income, throwout 

  • A person considered to be primitive, uncivilized and mentally deficient. 

  • A practice to avoid untaxed nowhere income by instead taxing such income in the originating state for a given transaction. 

  • A person similar to an ancestor, or something new similar to what already existed. 

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