Panama (ISO country code)

Public Attorney

Palestinian National Authority, interim organization that nominally governs parts of the West Bank and the Gaza Strip

Pennsylvania (United States postal abbreviation)

Pan American World Airways (Pan Am) (IATA airline designator)

Palo Alto, California

Peano arithmetic in mathematics

a series of paper sizes with 3:4 aspect ratio (most notably PA4)

Penny Arcade (webcomic), a popular gaming webcomic

Paisley, postcode of the town in Scotland

PA Consulting Group

Protactinium (Pa), symbol for the chemical element

Public administration

Performing artist

Pinkerton Academy, a school in Derry, NH

Phillips Academy, a private secondary school

Psoriatic arthritis

Pa, a word for dad or father ("pa" or "paw")

Panjabi language (ISO 639 alpha-2 language code)

Public address system, amplification equipment

Physician Assistant, the medical profession

People's Association, in Singapore

Piper Aircraft, as the type designator prefix for aircraft made by the company

Prince Albert piercing

Parental Advisory

PA-RISC family processor architecture from Hewlett-Packard

Princess Auto

Petayear, a calendar year or fiscal year for tax purposes

Picoampere, an SI unit of electric current (worth 10⁻¹² A)

Personal assistant

(live) Performance Artist

Production assistant, a title in the film industry

Polyacetylene (IUPAC name: polyethyne) is an organic polymer with the repeat unit (C2H2)n. The high electrical conductivity discovered for these polymers in the 1970’s accelerated interest in the use of organic compounds in microelectronics....

Pā (Māori), word meaning a fortified village or redoubt

Panic Alarm

Professional Association

Florida Coastal Airlines, IATA airline designator

Pascal (unit), SI unit of pressure

Polyamide, a kind of plastic

Press Association, a UK news agency

Public affairs

Pedophile activism

Pa (Chinese), political title meaning hegemon (pinyin: Ba)

Pa, one of the 8 departments of the Balé Province of Burkina Faso.

Petampere or Peta-ampere, an SI unit of electric current (worth 10¹⁵ A)

Plate appearance, a statistic in baseball.

Protonotary Apostolic, a Roman Catholic monsignor of the highest rank.