Ace – a serve that isn’t returned; results in a point for the server

Alley – the area along the court’s side walls, a “Down-the-Line” shot is targeted along this lane

Appeal – the process allowed in official tournament play through which a player may challenge the ruling of a “Line Judge”

Around-the-Wall Shot – a hard to return shot which travels from one side wall to the front wall, then the other side wall, before reaching the ground

Avoidable Hinder – a preventable and sometimes intentional movement to prevent an opponent from returning the ball, results in a loss of rally for the offending player:

Failure to Move – a player does not move away from the ball’s path in order to give his or her opponent the opportunity to return a shot

Stroke Interference – a player moves or does not move in a way that prevents the opponent from taking a full swing when attempting to return the ball

Moving into the Ball – stepping into the path of a ball being returned, preventing it from reaching its target  

Backhand – an essential stroke form beginning at the opposite side of the body from the racquet hand with the arm extended across the torso

Back wall – the wall running parallel to the “Front Wall” which players face away from during the serve; generally shots which intentionally reach or come close to the back wall are “Defensive Shots”
Bottom Board – the lowest point on the “Front Wall”; shots landing here are often unreturnable. See “Rollout.”

Bye – a guaranteed pass into the next round of a tournament, usually awarded to the top ranked players to allow them to bypass the first round without having to play a game

Ceiling Shot – when the ball hits the ceiling before it hits the front wall, it then hits the floor and takes a high bounce into the back court; generally a defensive shot used by highly skilled players to move their opponents from the safety of the “Center Court” position

Center Court – the most desirable position to hold on court, midway between the “Side Walls” and behind the “Short Line”

Cross-Court Pass – a shot passing the opponent on the way from one side of the court to the other

Cut-Throat – a racquetball variant for three players in which two players team up against the server, with players alternating at the server position.