probability

noun

prob·​a·​bil·​i·​ty ˌprä-bə-ˈbi-lə-tē 

plural probabilities

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

• liability
• likelihood

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

The probability of lightning strikes rises as a thunderstorm approaches and peaks when the storm is directly above. —Nc Weather Bot, Charlotte Observer, 11 May 2025

The probability of being attacked by a shark is one in four million. —Allegra Leal, New Yorker, 9 May 2025

In April a survey done by the National Association of Business Economics found that 37% of their forecasters believe there is a 50% or greater chance that an economic downturn will occur, with 50% of the participants rating the probability at between 25% and 49%. —Stephanie McNeal, Glamour, 7 May 2025

According to an article in Time Magazine, experts in the laws of scaling predict a 50% probability that AI will be able to perform any human task by 2047. —Michael Hicks, Forbes.com, 7 May 2025

Word History

First Known Use

15th century, in the meaning defined at sense 3

Phrases Containing probability

• conditional probability
• in all probability
• probability density
• probability density function
• probability distribution
• probability function

Rhymes for probability

• affability
• audibility
• bistability
• capability
• changeability
• contractility
• credibility
• culpability
• disability
• disutility
• durability
• fallibility

Kids Definition

probability

noun

prob·​a·​bil·​i·​ty ˌpräb-ə-ˈbil-ət-ē 

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