What does POW stand for in postal terminology?

In postal terminology, POW stands for "Prisoner of War." This term is used primarily in the context of military communications and the handling of mail for members of the armed forces who have been captured by enemy forces. The U.S. Postal Service has specific provisions and protocols regarding mail for prisoners of war to ensure that they can receive and send correspondence, which serves both to keep them connected with their loved ones and to provide them with necessary support during difficult times. The other terms presented are not established acronyms related to postal operations or communications, making "Prisoner of War" the appropriate definition in this context.