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

The Fed meets again at the end of the month and markets are pricing in a nearly 97% probability of another 25 basis point cut, according to the CME FedWatch tool . —Michelle Fox, CNBC, 14 Oct. 2025

This includes a 50% or higher probability of a night being 37 degrees or lower for two or more days in five-day span, rain for two or more consecutive days in the fall and winter and one day or night 32 degrees or lower. —Emma Hall, Sacbee.com, 14 Oct. 2025

Using that precise orbital data, Makadia's team simulated spacecraft impacts under a variety of conditions and projected Bennu's potential keyhole encounters, creating detailed impact-probability maps. —Sharmila Kuthunur, Space.com, 13 Oct. 2025

There is only a 30 percent probability of Connor offering surplus value at that price; there’s even a chance Connor’s game falls off precipitously in his mid-30s. —Murat Ates, New York Times, 9 Oct. 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