reason vs understanding

reason

noun
  • A motive for an action or a determination. 

  • That which causes something: an efficient cause, a proximate cause. 

  • An excuse: a thought or a consideration offered in support of a determination or an opinion; that which is offered or accepted as an explanation. 

  • A premise placed after its conclusion. 

  • Rational thinking (or the capacity for it); the cognitive faculties, collectively, of conception, judgment, deduction and intuition. 

verb
  • To support with reasons, as a request. 

  • To arrange and present the reasons for or against; to examine or discuss by arguments; to debate or discuss. 

  • To persuade by reasoning or argument. 

  • To find by logical process; to explain or justify by reason or argument. 

  • To deduce or come to a conclusion by being rational 

  • To overcome or conquer by adducing reasons. 

  • To perform a process of deduction or of induction, in order to convince or to confute; to argue. 

understanding

noun
  • The act of one that understands or comprehends; comprehension; knowledge; discernment. 

  • Opinion, judgement or outlook. 

  • An informal contract; mutual agreement. 

  • A reconciliation of differences. 

  • Sympathy. 

  • Reason or intelligence, ability to grasp the full meaning of knowledge, ability to infer. 

adj
  • Showing compassion, tolerance, and forbearance. 

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