A common feature of pinball games. During a multiball mode or feature, more than one ball is put into play at the same time, intentionally. The original intent of multiball was to provide an opportunity for a big reward to be achieved by making a difficult shot while simultaneously keeping two or more balls in play.

Originally it was a special game award to even be offered the chance to play multiball, and then you'd have two balls and could score special bonuses as long as you kept both in play, returning to normal play as soon as one ball drained.

Since then, pinball has suffered from multiball inflation in the same sense as score inflation and jackpot inflation, so that multiballs occur early and often, and with more balls. At some point three balls became the standard multiball, and some games started offering special multiballs with four, five, or six balls. Automatic plungers made these modes possible by allowing the game to shoot any number of balls into play when it wanted to, up to the limit of the number of balls stored in the machine. The maximum number of balls for multiball was in the Apollo 13 pinball which had a 13-ball mode, mostly as a joke, as most of the balls would rain into the outlanes out of control.

Williams Electronics trademarked Multiball, and as a result, Data East called it m-ball and tri-ball before they eventually licensed the term from Williams.