deduction vs rationale

deduction

noun
  • The ability or skill to deduce or figure out; the power of reason 

  • A conclusion; that which is deduced, concluded or figured out 

  • A process of reasoning that moves from the general to the specific, in which a conclusion follows necessarily from the premises presented, so that the conclusion cannot be false if the premises are true. 

  • That which is deducted; that which is subtracted or removed 

  • A sum that can be removed from tax calculations; something that is written off 

rationale

noun
  • A justification or rationalization for something. 

  • An explanation of the basis or fundamental reasons for something. 

  • A liturgical vestment worn by some Christian bishops of various denominations. 

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