Contact Points
The precise spot on the object ball's surface that the cue ball must strike.
What a contact point is
The contact point is the exact spot on the object ball's surface where the cue ball touches it at the moment of impact. It is the mirror image of the ghost ball concept: instead of visualizing where the cue ball must be, you visualize the point on the object ball itself, on the far side from the ghost ball position, along the same aiming line.
Full hits versus cuts
On a straight-in shot, the contact point sits on the back of the object ball, directly opposite the pocket. As the cut angle increases, the contact point rotates around the object ball's surface toward the side facing the cue ball, and it can be surprisingly far from where instinct suggests, especially on thin cuts. Many missed cuts come from misjudging how far around the ball the contact point has moved, not from a flawed stroke.
Using contact points to check your aim
A useful habit is to look at the object ball and physically identify the contact point before getting down on the shot, then confirm that your cue ball's path, extended forward, actually arrives there. Some players find visualizing the contact point more intuitive than visualizing the ghost ball, since it keeps your eyes on the real object ball rather than an imagined one.