probability

noun

plural probabilities
Synonyms of probability
1
a(1)
: the chance that a given event will occur
(2)
: 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
b
: a branch of mathematics concerned with the study of probabilities
2
: something (such as an event or circumstance) that is probable
3
: the quality or state of being probable
4
: a logical relation between statements such that evidence confirming one confirms the other to some degree

Synonyms of probability

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.
Recent Examples on the Web
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All registered voters were assigned a probability of voting to produce likely voter results. — ABC News, 18 Oct. 2026 That raises the possibility that investors are dangerously complacent about the probability of a rate hike in October. — Matt Peterson, CNBC, 16 Oct. 2026 Simulations accounting for a 4–6-kilometer-wide grounding zone suggest a 60-percent probability that the glacier will become unpinned from the Mouginot Ridge by the end of the century. — Neetika Walter, Interesting Engineering, 15 Oct. 2026 Farther east, including the I-35 corridor and the metroplex, rain chances will generally range from 30–50%, with lower probabilities toward our southeastern counties. — Michael Autovino, CBS News, 15 Oct. 2026 See All Example Sentences for probability

Word History

First Known Use

15th century, in the meaning defined at sense 3

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

Browse Nearby Words

Cite this Entry

“Probability.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/probability. Accessed 19 Oct. 2026.

Kids Definition

probability

noun
plural probabilities
1
: the quality or state of being probable
2
: something probable
3
a
: a measure of how often a particular event will happen if something which results in any of a number of possible events is done repeatedly
the probability of a coin coming up heads is ½
b
: a branch of mathematics concerned with the study of probabilities

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