AP
AP (Ability Points) are points that are used in the Kingdom Hearts series to equipped the game's characters with abilities. The overall AP can be increased by leveling up, using items such as AP Boost, or wearing equipment that will increase the overall AP. If the player does not have enough AP, they cannot equip certain skills until they have more AP or take off other abilities.
In Kingdom Hearts: Chain of Memories, AP is not used at all in Sora's gameplay, rather, it is replaced with "Learn Sleight" status growth. However, in Reverse/Rebirth, unrelated AP make an appearance as Attack Points in Riku's gameplay. The higher Riku's AP is, the stronger his attacks are.
Kingdom Hearts II
In this game the player can use ap boosts on all characters including Sora, Donald, Goofy, and supporting characters. There are a few AP Boosts in this game.