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noun rea·son \ˈrē-zən\

Simple Definition of reason

  • : a statement or fact that explains why something is the way it is, why someone does, thinks, or says something, or why someone behaves a certain way

  • : a fact, condition, or situation that makes it proper or appropriate to do something, feel something, etc.

  • : the power of the mind to think and understand in a logical way

Source: Merriam-Webster's Learner's Dictionary

Full Definition of reason

  1. 1 a :  a statement offered in explanation or justification <gave reasons that were quite satisfactory> b :  a rational ground or motive <a good reason to act soon> c :  a sufficient ground of explanation or of logical defense; especially :  something (as a principle or law) that supports a conclusion or explains a fact <the reasons behind her client's action> d :  the thing that makes some fact intelligible :  cause <the reason for earthquakes> <the real reason why he wanted me to stay — Graham Greene>

  2. 2 a (1) :  the power of comprehending, inferring, or thinking especially in orderly rational ways :  intelligence (2) :  proper exercise of the mind (3) :  sanity b :  the sum of the intellectual powers

  3. 3 archaic :  treatment that affords satisfaction

in reason

within reason

  1. :  within reasonable limits

with reason

  1. :  with good cause

Examples of reason in a sentence

  1. I gave a reason for my absence.

  2. Is there a reason for your strange behavior?

  3. There is a reason why they don't want to come.

  4. I can't give you the report for the simple reason that it isn't yet finished.

  5. She explained her reasons for deciding to change jobs.

  6. He wanted to know the reason for their decision.

  7. Give me one good reason why I should believe you.

  8. For obvious reasons, we can't do that yet.

  9. For reasons of space, some of the charts and graphs have been omitted from the article.

  10. She resigned for personal reasons.

Origin and Etymology of reason

Middle English resoun, from Anglo-French raisun, from Latin ration-, ratio reason, computation, from reri to calculate, think; probably akin to Gothic rathjo account, explanation

First Known Use: 13th century



verb rea·son

Simple Definition of reason

  • : to think in a logical way

  • : to form (a conclusion or judgment) by thinking logically

Source: Merriam-Webster's Learner's Dictionary

Full Definition of reason



play \ˈrēz-niŋ, ˈrē-zən-iŋ\
  1. intransitive verb
  2. 1 a obsolete :  to take part in conversation, discussion, or argument b :  to talk with another so as to influence actions or opinions <can't reason with them>

  3. 2 :  to use the faculty of reason so as to arrive at conclusions

  4. transitive verb
  5. 1 archaic :  to justify or support with reasons

  6. 2 :  to persuade or influence by the use of reason

  7. 3 :  to discover, formulate, or conclude by the use of reason <a carefully reasoned analysis>


play \ˈrēz-nər, ˈrē-zən-ər\ noun

Examples of reason in a sentence

  1. He lost the ability to reason.

  2. He reasoned that both statements couldn't be true.

  3. She reasoned that something must be wrong.

15th Century

First Known Use of reason

15th century

Synonym Discussion of reason

think, conceive, imagine, fancy, realize, envisage, envision mean to form an idea of. think implies the entrance of an idea into one's mind with or without deliberate consideration or reflection <I just thought of a good joke>. conceive suggests the forming and bringing forth and usually developing of an idea, plan, or design <conceived of a new marketing approach>. imagine stresses a visualization <imagine you're at the beach>. fancy suggests an imagining often unrestrained by reality but spurred by desires <fancied himself a super athlete>. realize stresses a grasping of the significance of what is conceived or imagined <realized the enormity of the task ahead>. envisage and envision imply a conceiving or imagining that is especially clear or detailed <envisaged a totally computerized operation> <envisioned a cure for the disease>.

think, cogitate, reflect, reason, speculate, deliberate mean to use one's powers of conception, judgment, or inference. think is general and may apply to any mental activity, but used alone often suggests attainment of clear ideas or conclusions <teaches students how to think>. cogitate implies deep or intent thinking <cogitated on the mysteries of nature>. reflect suggests unhurried consideration of something recalled to the mind <reflecting on fifty years of married life>. reason stresses consecutive logical thinking <able to reason brilliantly in debate>. speculate implies reasoning about things theoretical or problematic <speculated on the fate of the lost explorers>. deliberate suggests slow or careful reasoning before forming an opinion or reaching a conclusion or decision <the jury deliberated for five hours>.

REASON Defined for Kids



noun rea·son \ˈrē-zən\

Definition of reason for Students

  1. 1 :  a statement given to explain a belief or an act <My parents gave a reason for my absence.>

  2. 2 :  a fact that makes something right or fair to do <I have reasons for what I did.>

  3. 3 :  1cause 1 <The child wanted to know the reason for rain.>

  4. 4 :  the power to think and understand in a logical way

  5. 5 :  a fair and sensible way of thinking about something <He won't listen to reason.>



verb rea·son

Definition of reason for Students



  1. 1 :  to think in a logical way

  2. 2 :  to talk with another in a sensible way so as to influence his or her actions or opinions <“It's a fear you can't be … reasoned out of.” — Kate DiCamillo, Because of Winn-Dixie>

  3. 3 :  to state or ask logically <How, I reasoned, could such a thing happen?>

Law Dictionary


noun rea·son

Legal Definition of reason

  1. 1 :  an underlying ground, justification, purpose, motive, or inducement <required to provide reasons for the termination in writing>

  2. 2a :  the faculty of comprehending, inferring, or distinguishing especially in a fair and orderly way b :  the proper and sane exercise of the mind

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