Gambling is the act of wagering or betting money or something of value on an event with an uncertain outcome with the intent to win more money or things of value than was wagered. Gambling involves risking something of value, including money, for the chance of winning more than you risked.
In probability theory, odds provide a measure of the likelihood of a particular outcome. They are calculated as the ratio of the number of events that produce that outcome to the number that do not. Odds are commonly used in gambling and statistics.