A lottery is a form of gambling where numbers are selected and winners win prizes. This may be in the form of a lump sum or prize money spread over several years.

Historically, the practice of using lotteries for material gain dates from the time of the Roman Empire. The first known public lottery is thought to have been held during the reign of Emperor Augustus for the repair of city streets.

The lottery also became a popular way for the wealthy to distribute gifts during Saturnalian feasts and other social occasions. While this practice was not intended to be a means of making profits, it remained widespread for many centuries and was regarded as a legitimate form of taxation.

There are three main elements common to all lotteries: a pool of tickets, a drawing procedure, and a pool of prize money for winning prizes. Each of these elements must be well defined in order to achieve a level of integrity and fairness in the system.

In the United States, most states operate state lotteries. They include a variety of games, including instant-win scratch-offs and daily games that require the selection of two or more numbers.

The lottery industry has been the subject of controversy over its impact on society and on the economy. Critics have pointed to a range of issues, from the possible negative impact on problem gamblers to alleged regressive effects on lower-income groups. They argue that running a lottery at cross-purposes with the larger public interest is unwise and unnecessary.