A game in which prizes are distributed by chance or by the casting of lots. In general, the odds of winning a lottery prize are very low. A lottery is often used to raise money for public services. A lottery may include one large prize or several smaller prizes. In a private lottery, the prize is usually a valuable item or cash. Lotteries were widely used in colonial America to help finance public works projects, such as roads, libraries, churches, colleges, canals, and bridges.

The element that is common to all lotteries is some means of recording the identities and amounts staked by each participant. In some lotteries, this is done by hand; in others, it is done with the aid of computers. Once the identities and amounts are recorded, the tickets are thoroughly mixed (usually by some mechanical means, such as shaking or tossing) and then drawn in a procedure designed to ensure that only chance determines which bettors will win.

Lottery officials advertise the large prizes they offer. These are normally the proceeds that remain from the total pool of ticket sales after the costs of organizing and promoting the lottery, a percentage for profits to the promoter, and taxes or other revenues have been deducted. Most large-scale lotteries offer a single very large prize, and a number of smaller prizes. Many potential bettors are attracted to the promise of a very large jackpot, and this is often a driving force in ticket sales.