In discussing golf ball flight and curve, the Axis of Rotation is the imaginary line running through the center of the golf ball about which the golf ball spins. On all golf shots (except for topped shots and some putts) the top of the ball is rotating away from the target as the bottom of the ball is rotating towards the target. This is commonly referred to as backspin.


On golf shots that fly straight and on-target, the golf ball rotates about an axis that is parallel to the ground (perpendicular to the downward force of gravity) and perpendicular or square to the initial direction of flight. If the Axis of Rotation is tilted (like the wings on a plane as it banks to turn), the golf ball will Curve, flying laterally (to varying degrees) as it also flies forward, towards the target.