Topspin

In ball sports, topspin is a property of a ball that rotates as if rolling in the same direction as it is moving. Topspin on a shot imparts a downward force that causes the ball to drop, due to its interaction with the air (see Magnus effect). It can be generated by hitting the ball with an up-and-forward swing, with the racquet facing below the direction it is moving. A topspin shot is the opposite of the slice; topspin itself is the opposite of backspin.