reason
Americannoun
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a basis or cause, as for some belief, action, fact, event, etc..
the reasons for declaring war.
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a statement presented in justification or explanation of a belief or action.
I dare you to give me one good reason for quitting school!
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sufficient cause, as produced by a situation that makes an act, feeling, etc., obviously proper or appropriate.
After the mess he made of our yard, we have good reason to look for another landscaper.
- Synonyms:
- rationalization, excuse
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the mental powers concerned with forming conclusions, judgments, or inferences.
Effective leadership requires a person of reason.
- Synonyms:
- intelligence, mind, intellect, understanding
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sound judgment; good sense.
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normal or sound powers of mind; sanity.
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Logic. a premise of an argument.
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Philosophy.
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the faculty or power of acquiring intellectual knowledge, either by direct understanding of first principles or by argument.
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the power of intelligent and dispassionate thought, or of conduct influenced by such thought.
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Kantianism. the faculty by which the ideas of pure reason are created.
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verb (used without object)
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to think or argue in a logical manner.
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to form conclusions, judgments, or inferences from facts or premises.
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to urge reasons which should determine belief or action.
- Synonyms:
- persuade
verb (used with object)
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to think through logically, as a problem (often followed byout ).
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to conclude or infer.
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to convince, persuade, etc., by reasoning.
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to support with reasons.
idioms
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bring (someone) to reason, to induce a change of opinion in (someone) through presentation of arguments; convince.
The mother tried to bring her rebellious daughter to reason.
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in / within reason, in accord with reason; justifiable; proper.
She tried to keep her demands in reason.
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by reason of, on account of; because of.
He was consulted about the problem by reason of his long experience.
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stand to reason, to be clear, obvious, or logical.
With such an upbringing it stands to reason that the child will be spoiled.
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with reason, with justification; properly.
The government is concerned about the latest crisis, and with reason.
noun
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the faculty of rational argument, deduction, judgment, etc
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sound mind; sanity
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a cause or motive, as for a belief, action, etc
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an argument in favour of or a justification for something
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philosophy the intellect regarded as a source of knowledge, as contrasted with experience
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logic grounds for a belief; a premise of an argument supporting that belief
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because of
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within moderate or justifiable bounds
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it is logical or obvious
it stands to reason that he will lose
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to be persuaded peaceably
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political justifications for an immoral act
verb
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(when tr, takes a clause as object) to think logically or draw (logical conclusions) from facts or premises
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to urge or seek to persuade by reasoning
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to work out or resolve (a problem) by reasoning
Usage
The construction reason is because is criticized in a number of usage guides: The reason for the long delays was because the costs greatly exceeded the original estimates. One objection to this construction is based on its redundancy: the word because (literally, by cause ) contains within it the meaning of reason; thus saying the reason is because is like saying “The cause is by cause,” which would never be said. A second objection is based on the claim that because can introduce only adverbial clauses and that reason is requires completion by a noun clause. Critics would substitute that for because in the offending construction: The reason for the long delays in completing the project was that the costs. … Although the objections described here are frequently raised, reason is because is still common in almost all levels of speech and occurs often in edited writing as well. A similar charge of redundancy is made against the reason why, which is also a well-established idiom: The reason why the bill failed to pass was the defection of three key senators.
The expression the reason is because… should be avoided. Instead one should say either this is because… or the reason is that…
Synonym Usage
Reason, cause, motive are terms for a circumstance (or circumstances) which brings about or explains certain results. A reason is an explanation of a situation or circumstance which made certain results seem possible or appropriate: The reason for the robbery was the victim's display of his money. The cause is the way in which the circumstances produce the effect, that is, make a specific action seem necessary or desirable: The cause was the robber's extreme need of money. A motive is the hope, desire, or other force which starts the action (or an action) in an attempt to produce specific results: The motive was to get money to buy food for his family.
Other Word Forms
Derived Forms
Inflected Forms
Nouns
Participles
Conjugated Forms
Present
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reasonsimple
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reasonssimple
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have reasonedperfect
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has reasonedperfect
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am reasoningprogressive
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are reasoningprogressive
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is reasoningprogressive
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have been reasoningperfect progressive
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has been reasoningperfect progressive
Past
-
reasonedsimple
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had reasonedperfect
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was reasoningprogressive
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were reasoningprogressive
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had been reasoningperfect progressive
Future
Etymology
Origin of reason
First recorded in 1175–1225; Middle English resoun, reisun (noun), from Old French reisun, reson, from Latin ratiōn- (stem of ratiō ) ratio
Explanation
A reason explains why you do something. The reason you go to school is to learn things (and because it's the law). Reason usually has to do with thought and logic, as opposed to emotion. If people think you show good reason, or are reasonable, it means you think things through. If people think you have a good reason for doing something, it means you have a motive that makes sense. Reason can also be a verb. You might reason something out, which means that you look at all sides of the issue and then and decide what to do.
Vocabulary lists containing reason
Argumentative Writing
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Think Tank: Thought-Provoking Vocabulary
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Argumentative Writing, List 2
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
“Jean. I like Jean,” he responds, “she’s the villain but, like, there’s a reason to her madness.”
From Los Angeles Times ● Jul. 28, 2026
It takes work to get people to try something new, which is one reason for the promotional blitz that Paze launched in June.
From The Wall Street Journal ● Jul. 28, 2026
There is a simple reason for that: it is too expensive.
From BBC ● Jul. 28, 2026
The relative lack of automation compared to other manufacturers is part of the reason why the factory can only produce 10 planes per year.
From Barron's ● Jul. 28, 2026
For some reason, tears spill out of my eyes.
From "Keeping Pace" by Laurie Morrison
The case for a surprise increase when the rate-setting committee meets Wednesday rests less on anything members of the panel have signaled than on whether Chairman Kevin Warsh supports one for reasons of his own.
From The Wall Street Journal ● Jul. 29, 2026
Vaccines are one of the main reasons why we don’t have to worry about losing our kids.
From Los Angeles Times ● Jul. 28, 2026
But as the McInnes era prepares to kick into gear, are those same supporters heading into the new campaign with fewer reasons to fear more failure?
From BBC ● Jul. 28, 2026
This one, for reasons I can’t say I fully understand, skipped all that and went into effect immediately—as of today.
From Slate ● Jul. 28, 2026
It was the iced-over, heartless feeling that enables some people to do terrible things for what they believe are perfectly justifiable reasons.
From "The Long-Lost Home" by Maryrose Wood
I would totally hide Anne Frank, she reasoned.
From Slate ● Jul. 27, 2026
The researchers reasoned that the same enzyme might produce other peptides that influence energy balance and appetite.
From Science Daily ● Jul. 24, 2026
He reasoned that if the lodge was going to accommodate more than 20 guests, which was the intent, they’d need a massive great room.
From MarketWatch ● Jul. 6, 2026
By the end of the news conference, Feroli said, he was no closer to knowing how the committee now reasoned about policy.
From The Wall Street Journal ● Jun. 18, 2026
You’ve done this a hundred times, Koffi reasoned.
From "Beasts of Prey" by Ayana Gray
While Kennedy has refrained from commenting on the current court or President Trump, he has written a memoir that tells his life story and explains the reasoning behind the major decisions of his era.
From Los Angeles Times ● Jul. 26, 2026
But for complex reasoning tasks like managing AI agents, advanced coding problems and multistep research, frontier models perform better—even if by a small percentage—and that can make all the difference in outpacing the competition.
From The Wall Street Journal ● Jul. 17, 2026
Unlike closed, proprietary American systems from OpenAI or Anthropic, Kimi K3's open nature allows global users to modify the system for advanced reasoning and complex software development.
From BBC ● Jul. 17, 2026
All these decades later, I understand the calculus but remain baffled by that reasoning.
From Salon ● Jul. 15, 2026
If this reasoning is correct, then a search for deep geographic or ecological explanations will not be profitable.
From "Guns, Germs, and Steel: The Fates of Human Societies" by Jared M. Diamond
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
