Enhancement bonus

An enhancement bonus is a specific type of bonus that applies to:
 * AC for an armor that has been magically enhanced
 * Attack and damage rolls for a weapon that has been magically enhanced
 * A specific skill for some spells (like Jump) and some magic items (another kind of skill bonus is a competence bonus)
 * A specific ability for some spells (like Bull's strength) and some magic items

Enhancements bonuses do not stack (for instance the bonus given by Dexterous Boots would not stack with the bonus given by the Cat's Grace spell).