reservoir vs throwback

reservoir

noun
  • A species that acts as host to a zoonosis when it is not causing acute illness in other susceptible species. 

  • A "black box" component that receives an input signal to be read out and mapped by another process, as part of reservoir computing. 

  • A small intercellular space, often containing resin, essential oil, or some other secreted matter. 

  • A supply or source of something. 

  • A large natural or artificial lake used as a source of water supply. 

  • A place where anything is kept in store. 

verb
  • To store or keep (something) in or as in a reservoir. 

throwback

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

  • A reversion to an earlier stage of development. 

  • An atavism. 

  • Coordinate terms: nowhere income, throwout 

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

  • A person or thing that evokes memories. 

  • 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 reservoir and throwback occurred in a corpus of books? (source: Google Ngram Viewer )