Definition of probability has definitions from the field of statistics 1 [ noun ] (statistics) a measure of how likely it is that some event will occur Synonyms Examples "what is the probability of rain?" "we have a good chance of winning" Used in print(Frederick Mosteller et al., Probability with...) The binomial probability distribution may describe the variation that occurs from one set of trials of such a binomial experiment to another . We devote a chapter to the binomial_distribution not_only because it is a mathematical model for an enormous variety of real_life phenomena , but also because it has important properties that recur in many other probability models . What can we say of the probabilities of the different possible numbers of bull's-eyes ? What probabilities should be attached to these possible outcomes ? When three dice are tossed repeatedly , what is the probability that the number of aces is 0 ( or 1 , or 2 , or 3 ) ? 2 [ noun ] (statistics) the quality of being probable Used in print(Harry H. Hull, "The Normal Forces and Their Ther...) There is a well-known relationship between probability and entropy which states that * * f , where \q is the probability that state ( i.e. , volume for an ideal_gas ) could be reached by chance alone . There is a well-known relationship between probability and entropy which states that * * f , where \q is the probability that state ( i.e. , volume for an ideal_gas ) could be reached by chance alone . Related terms *