A match played in four ball (or fourball, or team match play) will see 2 golfers forming a team that will compete against the team made up by the other 2 golfers in the foursome. It is a variation of the better ball format, which itself is a type of best ball.
Each golfer hits his own ball throughout the round but only one score per team is recorded on each hole. After each hole, the best scores of both teams are compared and the team with the lowest score is said to have won the hole. The same thing occurs for every hole until the match ends.
How to win:
A team is declared the winner when its lead is such that the opposing team can no longer close the gap mathematically. For example, if team A is up 3 holes and there are 2 holes to play, team B winning the last two holes would still see it lose by 1. The match is thus ended, with a final score of 3 and 2 (3-up with 2 holes to play).
Four ball is very popular for season-long, ladder-type tournaments at golf clubs. It brings collaboration to the otherwise individual match play format.