noun prob·a·bil·i·ty \ˌprä-bə-ˈbi-lə-tē\

: the chance that something will happen

: something that has a chance of happening

: a measure of how often a particular event will happen if something (such as tossing a coin) is done repeatedly

plural prob·a·bil·i·ties

Full Definition of PROBABILITY

:  the quality or state of being probable
:  something (as an event or circumstance) that is probable
a (1) :  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 (2) :  the chance that a given event will occur
b :  a branch of mathematics concerned with the study of probabilities
:  a logical relation between statements such that evidence confirming one confirms the other to some degree


  1. There is a low probability that you will be chosen.
  2. There is some probability of rain tomorrow.
  3. With the dark clouds moving in, rain seems more like a probability than a possibility.
  4. The probability of a coin coming up heads is one out of every two tries.

First Known Use of PROBABILITY

15th century

Other Mathematics and Statistics Terms

abscissa, denominator, divisor, equilateral, exponent, hypotenuse, logarithm, oblique, radii, rhomb
PROBABILITY Defined for Kids


noun prob·a·bil·i·ty \ˌprä-bə-ˈbi-lə-tē\
plural prob·a·bil·i·ties

Definition of PROBABILITY for Kids

:  the chance of happening <The probability of rain is low.>
:  something likely <Rain is a probability.>
:  a measure of how likely a given event is <The probability of a coin landing face up is 1⁄2.>
June 30, 2015
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