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

According to the press release, there’s a 0.3% probability that these findings were a statistical fluke. —Chantelle Lee, Time, 17 Apr. 2025

On Wednesday, the FDA issued its recall classification as Class II, indicating the product may cause temporary or medically reversible adverse health effects, though the probability of serious harm is remote. —Thomas G. Moukawsher, MSNBC Newsweek, 17 Apr. 2025

The mathematics are sobering: While stocks offer relatively balanced upside/downside probabilities, gold's return distribution is heavily skewed. —Robert Daugherty, Forbes.com, 16 Apr. 2025

Confident in the algorithm's ability to recognize correlations, it was then applied to real observations, providing the 44 candidate planetary systems in which there is a high probability that an Earth-size planet exists in the habitable zone of its star. —Keith Cooper, Space.com, 16 Apr. 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