This is the amount of money an individual has to gamble with. It applies to all types of gambling, including betting on sports and card games. The term also applies to stacks of chips used to gamble in card games and other games of skill or chance in a casino.
The term comes from the roll of cash gamblers would have on hand before the advent of credit cards and ATM machines. Most individuals cannot bet on anything, let alone a sporting event, on credit. In some cases, official and unofficial sportsbooks will extend credit to worthy individuals based on their betting or work history. Notable celebrities and athletes will also receive credit under special circumstances. In the modern era, a bankroll is less visible because most gamblers do not walk around with rolls of cash. Many official sports books will accept debit cards or chips from the casino in addition to cash. Some may even accept a credit card.