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 of probability

• 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

This will give viewers the highest probability of spotting at least three planets at the same time, since Saturn, Mercury and Venus set in the west right after the sun. —Julia Jacobo, ABC News, 26 Feb. 2026

Slightly above-normal temperatures are projected for June, July and August, at a 33-40% probability. —Julia James, Dallas Morning News, 26 Feb. 2026

New in-game levers like the shot-in-the-dark and endless advantages have changed the game of Survivor to game theory that rewards probability calculation over spearing fish. —Kristen Geil, Outside, 24 Feb. 2026

One of the conditions that triggers the centers to open is if there is a 50% or higher probability of nighttime lows of 37 degrees or lower for two or more days within a five-day span. —Theresa Clift, Sacbee.com, 24 Feb. 2026

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