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

• 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

There are two primary strategies to keep in mind: Pre-Earnings Positioning: Evaluate the historical probabilities and take a stance before the earnings announcement. —Trefis Team, Forbes.com, 3 Aug. 2025

The Japanese government has repeatedly warned there is a 70-80% chance that Japan will be rocked by another Nankai Trough earthquake within 30 years – leading many scientists to questioning the accuracy of that probability. —Jessie Yeung, CNN Money, 3 Aug. 2025

The probability of lightning strikes rises as a thunderstorm approaches and peaks when the storm is directly above. —Ca Weather Bot, Sacbee.com, 2 Aug. 2025

For now the highest probability is just to the southwest of the New York City and New Jersey metro area, the weather service warned, but any shift northward would move the area of greatest potential rain closer into the city. —Dinah Voyles Pulver, USA Today, 31 July 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