Damage comes in many different flavors depending on the exact effect that causes damage. Each damage type has special rules that determine its exact effect. Injuries are also based on damage type. All damage has a type, and there is no such thing as 'untyped' damage.
Damage Types can also be broken up into some broader categories. Physical Damage represents any damage type that can be dealt by a mundane Weapon and includes, , , and damage. Alignment Damage is any damage type associated with one of the four alignments and includes , , , and damage. Elemental Damage includes all other damage types (i.e. those that are not Physical or Alignment damage types).