Power amplifier.
Public accountant.
Public Act.
Pennsylvania, a state of the United States of America
Papua, a province of Indonesia
Pará, a state of Brazil
Palestinian Authority
Proto-Algic (sometimes abbreviated PAc to distinguish it from Proto-Algonquian)
Proto-Athapaskan
Proto-Algonquian (sometimes abbreviated PAn to distinguish it from Proto-Algic, but usually just abbreviated PA with Proto-Algic being abbreviated PAc)
An electronic voice-amplification apparatus, usually containing a set of two loudspeakers and a central control unit, used for singing, giving a speech, play-by-play commentary at events, or broadcasting in public areas like in airports or stations.