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

What the result does, and does not establish The study shows that Aumann’s Agreement Theorem is not limited to classical probability or quantum theory. — Rupendra Brahambhatt, Interesting Engineering, 19 Sep. 2026

Improved logistics for Saudi crude exports have reduced the market's assessment of how much supply is at risk, Massabni said, adding that oil prices reflect not just available barrels but also the probability of those supplies being disrupted. — Lee Ying Shan, CNBC, 18 Sep. 2026

Let’s take a guess at probabilities for Sunday’s starter, because math is (sometimes) fun. — Daniel Flick, AJC.com, 17 Sep. 2026

A lot of people in the world of artificial intelligence are talking about their P(doom) number, which is the probability that artificial intelligence will lead to an absolutely catastrophic situation—possibly, or probably, killing us all. — Tyler Foggatt, New Yorker, 17 Sep. 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