Weapon Finesse

Combat

You are trained in using your agility in melee combat, as opposed to brute strength.

Benefit: With a light weapon, elven curve blade, rapier, whip, or spiked chain made for a creature of your size category, you may use your Dexterity modifier instead of your Strength modifier on attack rolls. If you carry a shield, its armor check penalty applies to your attack rolls.

Special: Natural weapons are considered light weapons.

Source: Pathfinder Core Rulebook