| Noun | 1. | probability - a measure of how likely it is that some event will occur; a number expressing the ratio of favorable cases to the whole number of cases possible; "the probability that an unbiased coin will fall with the head up is 0.5" quantity, measure, amount - how much there is or how many there are of something that you can quantify conditional probability, contingent probability - the probability that an event will occur given that one or more other events have occurred cross section - (physics) the probability that a particular interaction (as capture or ionization) will take place between particles; measured in barns exceedance - (geology) the probability that an earthquake will generate a level of ground motion that exceeds a specified reference level during a given exposure time; "the concept of exceedance can be applied to any type of environmental risk modeling" fair chance, sporting chance - a reasonable probability of success fat chance, slim chance - little or no chance of success joint probability - the probability of two events occurring together risk of exposure, risk - the probability of being exposed to an infectious agent risk of infection, risk - the probability of becoming infected given that exposure to an infectious agent has occurred |
| 2. | probability - the quality of being probable; a probable event or the most probable event; "for a while mutiny seemed a probability"; "going by past experience there was a high probability that the visitors were lost" quality - an essential and distinguishing attribute of something or someone; "the quality of mercy is not strained"--Shakespeare likelihood, likeliness - the probability of a specified outcome improbability, improbableness - the quality of being improbable; "impossibility should never be confused with improbability"; "the improbability of such rare coincidences" |