PA

* Power armor, a type of mechanized cavalry armor appearing in every game in the Fallout series.
* Pennsylvania, a pre-War state in the former United States of America.
* Public address systems, examples of which include:
** Vault 101 PA System, within Vault 101 in Fallout 3.
** D.B. Technical High School/PA system, within D.B. Technical High School in Fallout 4.
** DMV PA System, within the Charleston Capitol Department of Motor Vehicles in Fallout 76.
** Mama Dolce's PA System, within Mama Dolce's Food Processing in Fallout 76.