reason

noun
  1. A cause, explanation, or justification for an action or event. noun
    The reason for the delay was the heavy traffic.
    She gave a valid reason for her absence from the meeting.
  2. The power of the mind to think, understand, and form judgments logically. noun
    Humans have the ability to reason and solve complex problems.
    He used reason to come to a fair decision.
  3. To think, understand, and form judgments by a process of logic. verb
    She reasoned that it was too late to start the journey.
    He reasoned with his friend to convince him to stay.