PSA

PSA may refer to:
 * PSA International (formerly Port of Singapore Authority), world's second largest port operator
 * PSA Peugeot Citroën, French vehicle manufacturer
 * PSA prepayment model, developed by the Bond Market Association (formerly the Public Securities Association)
 * Primary Systemic Amyloidosis, in which a human body produces "bad proteins"
 * Pressure-sensitive adhesive
 * Prostate-specific antigen, a protein that helps to identify prostate cancer in a widely used test
 * Public service announcement
 * Probabilistic safety assessment
 * "PSA", precursor to the R.E.M. song "Bad Day"
 * "Pseudomonas syringae actinidiae", a variety of a bacteria Pseudomonas syringae that attacks kiwifruit

Airlines and airports

 * PSA Airlines, a subsidiary of US Airways, Inc.
 * PSA, ICAO code for Pacific Southwest Airlines, an American airline that operated from 1949 to 1988
 * PSA, IATA code for Galileo Galilei Airport, Pisa, Italy

Chemistry

 * Polar surface area, the surface sum over all polar atoms of a molecule
 * Pressure swing adsorption, a technology for purifying gases

Computing

 * Plesk Server Administrator, a commercial web hosting automation program
 * Professional services automation software, a project and resource management suite

Contracts, legislation, and government

 * Passenger Vessel Services Act of 1886, also known as the Passenger Services Act, United States cabotage legislation
 * Production sharing agreement, a contract between a government and a resource extraction company
 * Public service agreement, details the aims and objectives of UK government departments for a three-year period

Organizations

 * Photographic Society of America
 * Pacific Science Association
 * Philosophy of Science Association
 * Professional Squash Association
 * World Indoor Soccer League (formerly the Premier Soccer Alliance)

Australia

 * Pharmaceutical Society of Australia
 * Public Service Association of NSW, a trade union
 * Public Schools Association, Perth
 * The Salvation Army, Parramatta, Sydney

New Zealand

 * New Zealand Public Service Association, a trade union

Pakistan

 * Pakistan Student Association

Philippines

 * Philippine Support Association, a group that raises credit for the poor

Poland

 * Polish Society of Actuaries

South Africa

 * Public Servants Association of South Africa, a trade union

Spain

 * Andalusian Party, a political party

Trinidad and Tobago

 * Public Services Association, a trade union

United Kingdom

 * Political Studies Association, an academic association
 * Professional Speaking Association
 * Property Services Agency, a former UK government agency

United States

 * Photographic Society of America
 * Pi Sigma Alpha
 * Poultry Science Association

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