Damage (hit points)
Damage describes the removal of hit points from a combatant due to hits from weapons, spells, the elements, falling, disease or other source (there are many possibilities). When damage occurs, the amount is temporarily struck off the character's present hit points, until such time as these points can be healed through magic or rest.
Out of game, damage measures the character's nearness to death; as damage accumulates, the character is driven towards negative hit points, and thereafter to unconsciousness and death. Sufficiently high amounts of damage may cause a wound or an injury. These last two give clues to the representation of damage "in game" — that it is, for the most part, a wearing down of the character, through nicks, small cuts, bruising and exhaustion.
When the character is actually wounded, then damage begins to accrue continuously. Unconsciousness indicates that the character is so tired and hurt that they must succumb. When an injury occurs, it is because there has been some breaking of the bone, or moderate damage to one of the combatant's organs. Injuries cannot indicate severe trauma, as being that the game takes place in pre-Industrial times, that would mean the equivalent of death (-10 or more hit points).
Levelled characters can sustain far more damage than non-levelled. This is considered due to training, resilience and an comparative indifference to a hurt that would severely disable a more common person, but which a levelled character shrugs off.