retraction vs reversal

retraction

noun
  • An act or instance of retracting. 

  • A continuous function from a topological space onto a subspace which is the identity on that subspace. 

  • A statement printed or broadcast in a public forum which effects the withdrawal of an earlier assertion, and which concedes that the earlier assertion was in error. 

reversal

noun
  • An instance of reversing. 

  • A change in fortune; a change from being successful to having problems. 

  • The state of being reversed. 

adj
  • Intended to reverse; implying reversal. 

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