In Australia, it might be called Irish Four Ball. In the U.K., a bowmaker. In the United States, 1-2-3 best ball or money ball, among other possible names and variations.
Fourball alliance is typically played using Stableford scoring by four-person teams. Each team member plays his or her own ball throughout. And on each hole, a predetermined number of team member's scores are combined for one team score.
Most commonly, the best two scores among the four team members are combined. So let's say that on the first hole, the scores of the four team members are 0, 0, 1 and 2 (remember, fourball alliance is usually played with Stableford scoring). The 1 and the 2 are the two best scores, so the team score is 3 (1 plus 2).
If fourball alliance is played as standard stroke play, and team members' scores are 4, 5, 6 and 7, the team score would be 9 (4 plus 5).

