subduction vs substraction

subduction

noun
  • Arithmetical subtraction. 

  • The process of one tectonic plate moving beneath another and sinking into the mantle at a convergent plate boundary. 

  • The action of being pushed or drawn beneath another object. 

  • A surjection between diffeological spaces such that the target is identified as the pushforward of the source. 

  • The act of subducting or taking away. 

substraction

noun
  • Subtraction. 

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