In tennis, "Ad" stands for "advantage." This term is used when the score is tied at 40-40, known as "deuce." After deuce, the player who wins the next point gains the advantage, meaning they are one point away from winning the game. If the player with the advantage wins the following point, they win the game. However, if they lose the next point, the score returns to deuce, and play continues until one player wins two consecutive points
. The score is often announced as "Ad-In" if the server has the advantage, and "Ad-Out" if the receiver has it. This scoring system requires a player to win by two clear points after deuce to claim the game
