Attack Damage

Attack Damage is the amount of damage the Basic Attacks from a Champion deal with each hit. This statistic can also increase the damage of some skills. Attack Damage is color-coded orange in skill tooltips.

Champions who's skills scale off bonus Attack Damage are called "Attack Damage champions". You can find a list of them here: Attack Damage champions

There are also several Artifacts that provide bonus Attack Damage. You can find a list with these artifacts here: Attack Damage artifacts