The ball crosses the line between the posts and beneath the crossbar. The referee points to the center circle. That score is a goal. In many sports it is the primary way of gaining points.

Goals can be moments of individual brilliance or the product of sustained team build-up. Defenders and goalkeepers exist largely to prevent them. The emotional release that follows a goal—celebration for one side, disappointment for the other—gives matches their drama.

Rules define what constitutes a valid goal, including offside, the ball’s full crossing of the line, and the absence of infringements in the build-up. Technology such as goal-line systems has reduced uncertainty in close cases. The pursuit and prevention of goals organize almost every tactical decision on the field.

Few moments in sport are as clear or as decisive as the ball hitting the net.