Article 4 defines prisoners of war to include:
4.1.1 Members of the armed forces of a Party to the conflict and members of militias of such armed forces
4.1.2 Members of other militias and members of other volunteer corps, including those of organized resistance movements, provided that they fulfill all of the following conditions:
that of being commanded by a person responsible for his subordinates;
that of having a fixed distinctive sign recognizable at a distance (there are limited exceptions to this among countries who observe the 1977 Protocol I);
that of carrying arms openly;
that of conducting their operations in accordance with the laws and customs of war.
4.1.3 Members of regular armed forces who profess allegiance to a government or an authority not recognized by the Detaining Power.
4.1.4 Civilians who have non-combat support roles with the military and who carry a valid identity card issued by the military they support.
4.1.5 Merchant marine and the crews of civil aircraft of the Parties to the conflict, who do not benefit by more favourable treatment under any other provisions of international law.
4.1.6 Inhabitants of a non-occupied territory, who on the approach of the enemy spontaneously take up arms to resist the invading forces, without having had time to form themselves into regular armed units, provided they carry arms openly and respect the laws and customs of war.
4.3 makes explicit that Article 33 takes precedence for the treatment of medical personnel of the enemy and chaplains of the enemy.