使球旋转 meaning in English

bending the ball

The pitcher gave a spin to the ball
投手使球旋转。
The server shall then project the ball near vertically upwards , without imparting spin , so that it rises at least 16cm after leaving the palm of the free hand and then falls without touching anything before being struck
发球员须用手将球几乎垂直地向上抛起，不得使球旋转，并使球在离开不执拍手的手掌之后上升不少于16公分，球下降到被击出前不能碰到任何物体。