Definition

1. Noun:

   • A cause, explanation, or justification for an action, event, or belief: A fact or circumstance that provides logical grounds for something.
   • The power of the mind to think, understand, and form judgments logically: The capacity for rational, analytical thought.
   • What is right, practical, or possible; good sense: Conformity with logic or sensible thinking.

2. Verb:

   • To think, understand, and form judgments by a process of logic: To use the faculty of reason.
   • To persuade someone with logical arguments: To try to convince someone by presenting reasoned points.
   • To conclude or work something out by using logic: To reach a judgment or solution through a process of reasoning.

Examples of Usage

• Noun:

  • The main reason for his resignation was the lack of support. (The cause or justification for his action.)
  • Human beings possess the faculty of reason. (The capacity for logical thought.)
  • It's important to listen to reason. (To listen to sensible, logical advice.)

• Verb:

  • We need to reason this problem through carefully. (To think about it logically.)
  • She tried to reason with him, but he was too angry. (To persuade him using logical arguments.)
  • From the evidence, we can reason that the suspect was present. (To conclude logically.)

Advanced Usage

• "within reason": Within sensible or moderate limits; not excessive.

  • You can decorate your room however you like, within reason. (As long as it is sensible and not extreme.)

• "it stands to reason": It is logical or obvious to conclude.

  • It stands to reason that if you practice more, you will improve. (It is a logical conclusion.)

• "by reason of": Because of; due to (formal).

  • The event was canceled by reason of bad weather. (Because of bad weather.)

Variants and Related Words

• Reasonable (adj): Based on good sense; fair and sensible.

  • She made a reasonable request. (A fair and sensible request.)

• Reasoning (n): The process of thinking about something in a logical way to form a conclusion or judgment.

  • His reasoning was flawed. (His logical process was incorrect.)

• Reasoned (adj): Based on logic or good sense.

  • She presented a reasoned argument. (A logical and well-thought-out argument.)

Synonyms

• Noun (cause): Cause, grounds, basis, justification, motive.
• Noun (logic): Intellect, rationality, logic, judgment, sense.
• Verb: Think, deduce, infer, conclude, argue, persuade.

Related Phrasal Verbs

• Reason out: To find an answer or solution to something by thinking about it logically.

  • Let's sit down and reason out the best course of action. (Think it through logically to find the best plan.)

• Reason with: To try to persuade someone to be sensible by talking to them in a logical way.

  • It's useless to reason with him when he's in this mood. (To try to persuade him logically.)

Related Idioms

• "lose one's reason": To become insane or irrational.

  • The tragic news caused him to lose his reason. (To become mentally unbalanced.)

• "rhyme or reason": Logical explanation or sense (often used in the negative).

  • There's no rhyme or reason to his decisions. (His decisions make no logical sense.)

Noun

1. a fact that logically justifies some premise or conclusion
   • there is reason to believe he is lying
2. a justification for something existing or happening
   • he had no cause to complain
   • they had good reason to rejoice
3. the state of having good sense and sound judgment
   • his rationality may have been impaired
   • he had to rely less on reason than on rousing their emotions
4. the capacity for rational thought or inference or discrimination
   • we are told that man is endowed with reason and capable of distinguishing good from evil
5. an explanation of the cause of some phenomenon
   • the reason a steady state was never reached was that the back pressure built up too slowly
6. a rational motive for a belief or action
   • the reason that war was declared
   • the grounds for their declaration

Verb

1. think logically
   • The children must learn to reason
2. present reasons and arguments
3. decide by reasoning; draw or come to a conclusion
   • We reasoned that it was cheaper to rent than to buy a house