prob·​a·​bil·​i·​ty | \ ˌprä-bə-ˈbi-lə-tē How to pronounce probability (audio) \
plural probabilities

Definition of probability

1 : the quality or state of being probable
2 : something (such as an event or circumstance) that is probable
3a(1) : the ratio of the number of outcomes in an exhaustive set of equally likely outcomes that produce a given event to the total number of possible outcomes
(2) : the chance that a given event will occur
b : a branch of mathematics concerned with the study of probabilities
4 : a logical relation between statements such that evidence confirming one confirms the other to some degree

Synonyms & Antonyms for probability



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Examples of probability in a Sentence

There is a low probability that you will be chosen. There is some probability of rain tomorrow. With the dark clouds moving in, rain seems more like a probability than a possibility. The probability of a coin coming up heads is one out of every two tries.
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Recent Examples on the Web There is a low probability of widespread hazardous weather, according to the NWS. Emily Deletter, The Enquirer, 26 Oct. 2021 The danger is the probability that some illegitimate future inquiry will be used to achieve illegitimate ends. Jelani Cobb, The New Yorker, 3 Oct. 2021 The researchers found that participants with OCD symptoms were more avoidant of low probability negative outcomes in the game. Mark Travers, Forbes, 6 Sep. 2021 Campbell indicated there is a high probability the Lions add more offensive line depth in the coming days off the waiver wire or via trade. Dave Birkett, Detroit Free Press, 30 Aug. 2021 The Princeton University researchers behind the paper found that there's a less than 1 percent probability that the changes occurred naturally. NBC News, 12 Aug. 2021 There is the future probability of using the app to give drivers access to future financial products like insurance. Alexander Onukwue, Quartz, 9 Aug. 2021 As for the back end of the tournament, on-site meteorologist Kyle Koval calls for possible showers and storms on Saturday evening, with a rain probability of 20%. Scott Bell, Dallas News, 14 May 2021 Of course, the potential of a nuclear exchange always exists between nuclear powers, but since such a step could very well mean the end of Xi Jinping’s reign and even that of the Chinese Communist Party, the probability is quite low. Washington Post, 29 Oct. 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'probability.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of probability

15th century, in the meaning defined at sense 1

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Time Traveler for probability

Time Traveler

The first known use of probability was in the 15th century

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Dictionary Entries Near probability



probability curve

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Statistics for probability

Last Updated

28 Nov 2021

Cite this Entry

“Probability.” Dictionary, Merriam-Webster, Accessed 2 Dec. 2021.

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More Definitions for probability



English Language Learners Definition of probability

: the chance that something will happen
: something that has a chance of happening
: a measure of how often a particular event will happen if something (such as tossing a coin) is done repeatedly


prob·​a·​bil·​i·​ty | \ ˌprä-bə-ˈbi-lə-tē How to pronounce probability (audio) \
plural probabilities

Kids Definition of probability

1 : the chance of happening The probability of rain is low.
2 : something likely Rain is a probability.
3 : a measure of how likely a given event is The probability of a coin landing face up is ¹/₂.

More from Merriam-Webster on probability

Nglish: Translation of probability for Spanish Speakers

Britannica English: Translation of probability for Arabic Speakers Encyclopedia article about probability


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