A second set is one that is played in the center of the court near the net, generally to the middle hitter. A one-set is a brief middle set. A three-set is a rapid set halfway between the outer and the center. A back-set to the right-side hitter is a five-ball. To the left-side hitter, it's a four-ball. The term "second set" may also be used to describe any subsequent set played by either team while the first set is still being played. So for example, if you were to watch a women's volleyball game and saw that set one was being played then set two would be going off after set one was finished, this set two would be the second set. As another example, if set one ended in a tie score, then there would be a third set played with each team receiving two balls. This third set would be the second set. There are several terms used to describe different numbers of sets in a volleyball game.