Unconscious
From FOnline: Aftertimes
The term unconscious refers to the state of an NPC or a PC who is lying on the ground devoid of any APs and hence unable to do anything.
This may be either as a result of a knock-out, or as a result of severe injuries that resulted in the poor person's hit points reaching a negative value. If left alone, their hit points will regenerate and they might stand again. Otherwise stimpaks or First Aid can be used to try to revive such characters.