Meaning : A short-lived radioactive metallic element formed from uranium and disintegrating into actinium and then into lead.
Synonyms : atomic number 91, protactinium, protoactinium
Meaning : A Mid-Atlantic state. One of the original 13 colonies.
Synonyms : keystone state, pa., pennsylvania
Meaning : An electronic amplification system used as a communication system in public areas.
Synonyms : p.a., p.a. system, pa system, public address system