ATP in tennis stands for the Association of Tennis Professionals, which is the governing body of the mens professional tennis circuits, including the ATP Tour, the ATP Challenger Tour, and the ATP Champions Tour. The ATP Tour includes ATP 250, ATP 500, and ATP Masters 1000 events, which denote the number of Pepperstone ATP Rankings points awarded to the champion. The ATP rankings are used for determining qualification for entry and seeding in all tournaments for both singles and doubles. The player with the most points by the seasons end is the world No. 1 of the year.