How likely something is to happen, usually expressed as the ratio of the number of ways the outcome may occur to the number of total possible outcomes for the event. For instance, each time you throw a dice there are six possible outcomes, but in only one of these can a six come up. Thus the probability of throwing a six on any given throw is one in six. The fact that you threw a six last time does not alter the one-in-six probability of throwing a six next time (see risk).