- Absence of military (notes): This list shows countries that have no permanent army, whose defense has been assigned to non-military forces such as the police, or is assumed by the military forces from other countries by virtue of a treaty. Each entry describes the current status of each country on regards to its defense.
- Branches: The names of the ground, naval, air, marine, and other defense or security forces
- Military branches: This entry lists the service branches subordinate to defense ministries or the equivalent (typically ground, naval, air, and marine forces).
- Military service age and obligation: This entry gives the required ages for voluntary or conscript military service and the length of service obligation.