HP

HP are most commonly refereed to as hit points. They determine a characters staying power against obstacles which harm you, when you hit zero the character is rendered useless under most circumstances. Hit points are notoriously abstract in that they don't logically have a representation in the real world despite the name. For example the most common way to lose HP is to take damage from a weapon, yet in systems where you gain HP upon leveling up you may not die from the same gun shot that would have killed you last level.