Read the dictionary definition of PA. All definitions for this word.
1. an electronic amplification system used as a communication system in public areas
2. a Mid-Atlantic state; one of the original 13 colonies
3. an informal term for a father; probably derived from baby talk
4. a unit of pressure equal to one newton per square meter
5. a short-lived radioactive metallic element formed from uranium and disintegrating into actinium and then into lead