Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

English definition of “reason”

reason

noun uk   /ˈriː.zən/ us  

reason noun (EXPLANATION)

A2 [C or U] the cause of an event or situation or something that provides an excuse or explanation: The reason for the disaster was engine failure, not human error. [+ question word] The reason why grass is green was a mystery to the little boy. [+ (that)] The reason (that) I'm calling is to ask a favour.not standard The reason I walked out was because I was bored. [+ to infinitive] The police have (every good) reason to believe that he is guilty. She was furious, and with reason (= with good cause). For some reason/For reasons best known to himself (= for reasons no one else knows about) he's decided to leave his job.Motives and reasonsReasons and explanations by reason of formal because of: He's always asked to these occasions by reason of his position.Connecting words which introduce a cause or reason

reason noun (JUDGMENT)

[U] the ability of a healthy mind to think and make judgments, especially based on practical facts: We humans believe that we are the only animals to have the power of reason.mainly UK old-fashioned He lost his reason (= became mentally ill) when both his parents were killed in the crash.Mind and personalityScience of psychology and psychoanalysis within reason C2 within the limits of what is acceptable and possible: We can wear anything we like to the office, within reason.Suitable and acceptableQuite good, or not very good

reason

verb [T] uk   /ˈriː.zən/ us  
to try to understand and to make judgments based on practical facts: [+ (that)] Newton reasoned (that) there must be a force such as gravity, when an apple fell on his head. I spent hours reasoning out the solution to the puzzle.Thinking and contemplatingConcluding and deducing
Phrasal verbs
(Definition of reason from the Cambridge Advanced Learners Dictionary & Thesaurus © Cambridge University Press)
What is the pronunciation of reason?
Add Cambridge dictionaries to your browser to your website

Definitions of “reason” in other dictionaries

Word of the Day

stampede

When animals or people stampede, they all move quickly in the same direction, often because they are frightened.

Word of the Day

Blog

Read our blog about how the English language behaves.

Learn More

New Words

Find words and meanings that have just started to be used in English, and let us know what you think of them.

Learn More