What does "ball in" mean in basketball? "ball in" can be used in different places in basketball. After the ball has gone out of bounds and play has been stopped, it signifies that the ball becomes live and play has started. In general, it's said to prevent one side from gaining advantage on a restart of stopped play. 1. In a full game, the ref can say "ball in", indicating that an out-of-bounds player can throw the ball to his teammate to restart play. 2. Most basketball is not played with refs on a full-sized court. It's played on a half-court with one basket and usually the only boundary lines are near the basket. Play typically restarts after a player from the other team passes you the ball. You could say "ball in" to indicate that this puts the ball into play. Another common variant would be the player who is going to have possession would pass it to someone on the other team, who then passes it back. This is called a "check".

The sport of basketball involves scoring by putting a ball though a basket.