The term for when a player wins a point after a second serve is "second serve ace" or "second serve winner."
A "second serve ace" or "second serve winner" occurs when a player hits a winning shot after their second serve. In tennis, players are allowed two attempts to serve during each point. If the first serve is unsuccessful, the player must serve again, and this is known as the second serve. A successful second serve that wins the point outright is considered a second serve ace or winner. Second serve aces are less common than first serve aces and are often seen as a sign of a player's skill and composure under pressure.