The "stroke" is often the most misunderstood and most difficult to define part of the game. While we may be unable to put it into words - we know it when we see it. The stroke is what separates the good from the great. The stroke must be smooth; it must be straight; it must be complete. We know it when we "feel" it: the grip (the position of the fingers on the butt), the alignment (head, shoulders, elbows, wrist), the execution (the lock of the eyes on the object ball, the feel of the cue as it contacts the CB.
The stroke can be taught, but ultimately the player will become his own best teacher. It is his/her responsibility to listen to every ligament and cell and to constantly adjust. Adjust to the conditions (humidity, temperature), adjust to the table (speed, rails, balls). The greatest players are great because they have the ability to "adjust". From the inside out they are constantly tuning their bodies, polishing the roughness, smoothing muscle movements. They have learned to "listen" to their bodies. They have worked out all obstacles to a flawless execution. They have the "stroke".