League of Legends (LoL) players use AP to stand for Ability Power. This stat adds power to certain abilities, items, and runes.
For example, the item Nashor's Tooth gives your champion +100 AP and makes your champion's basic attacks deal 15 + 20% AP additional damage. This means that, by itself, Nashor's Tooth makes your basic attacks deal 35 additional damage. Any additional AP your champion possesses (either inherently or from other items) will increase Nashor's Tooth's power.
Example
Some champions scale with AP a lot better than others, so you should consider who on your team is best suited for items that enhance AP
League of Legends (LoL) players use AP to stand for Ability Power. This stat adds power to certain abilities, items, and runes.
For example, the item Nashor's Tooth gives your champion +100 AP and makes your champion's basic attacks deal 15 + 20% AP additional damage. This means that, by itself, Nashor's Tooth makes your basic attacks deal 35 additional damage. Any additional AP your champion possesses (either inherently or from other items) will increase Nashor's Tooth's power.