Entity: Precision

Source Player Core pg. 154 ^2.0

You have trained to aim for your prey’s weak points. The first time you hit your hunted prey in a round, you also deal 1d8 additional precision damage. (Precision damage increases the damage you already deal, using the same type, but is ineffective against creatures that lack vital organs or weak points.) At 11th level, the extra damage increases to 2d8 precision damage, and at 19th level, the extra damage increases to 3d8 precision damage.

Your weapon mastery allows you to hit your prey’s vital areas multiple times. The second time in a round you hit your hunted prey, you also deal 1d8 precision damage. At 19th level, your second hit in a round against your hunted prey deals 2d8 precision damage, and your third hit in a round against your hunted prey deals 1d8 precision damage.