It is damage - which is always vague in d20
Its a consistency issue, Vincent. For some illogical reason, hitting it with a weapon can cause the weapon to shatter, unless of course the weapon is your fist (absolutely inconsistent).
I think damage is totally backwards in some RPGs. A living being is extremely complicated, thus a blow that damages a vital organ can instantly kill. An object, on the other hand, usually has to be battered about a bit before it ceases to function.
I believe a damage type such as Light, Major, Severe, and Critical, that addresses the condition of a wound, can more directly portray damage done to a living being.
Massive Damage attempts to give more realism to the game, but the amount of 20 points of damage is still arbitrary.
Any weapon used in warfare can kill in a single blow, they are designed to do just that. Giving a weapon a certain amount of damage points, such as 1d4 for a knife, means that in normal combat, even with a critical hit, you will never kill your opponent in one single blow. If instead, you use Light, Major, Severe, or Critical damage done, then any weapon can kill with a single blow.
But that would be a totally different game.