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

The price of that contract changes with the probability of the outcome. —Paolo Confino, Fortune, 5 Nov. 2024

Pollster Nate Silver's Silver Bulletin projects an even wider margin, with Trump at a 53.8 percent probability of winning to Harris' 45.8 percent. —Marco Rubio, Newsweek, 2 Nov. 2024

Offshore bettors have pushed up the probability of Trump winning all but two of those states. —Jim Sergent, USA TODAY, 31 Oct. 2024

Harris wins, but the government is divided A 40% probability, with the S & P 500 to fall 1.5% This scenario has the greatest likelihood to come true of the four possible election outcomes. —Sarah Min, CNBC, 5 Nov. 2024

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

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