Biology and medicine
* Accessible surface area of a biomolecule, accessible to a solvent * Acetylsalicylic acid, aspirin * Advanced surface ablation, refractive eye surgery * Anterior spinal artery, the blood vessel which supplies the anterior portion of the spinal cord * Antisperm antibodies, antibodies against sperm antigens * Argininosuccinic aciduria, a disorder of the urea cycle * ASA physical status classification system, rating of patients undergoing anesthesiaEducation and research
* African Studies Association of the United Kingdom * African Studies Association *Alandica Shipping Academy, Åland Islands, Finland * Albany Students' Association, at Massey University, Auckland, New Zealand * Alexander-Smith Academy, in Houston, Texas * Alpha Sigma Alpha, U.S. national sorority * American Society for Aesthetics, philosophical organization * American Student Assistance, national non-profit organization * American Studies Association * Arizona School for the Arts * Armenian Sisters Academy * Association of Social Anthropologists * Astronomical Society of Australia * Austrian Studies AssociationOrganizations
* Acoustical Society of America, international scientific society * Advertising Standards Authority (disambiguation), advertising regulators in several countries * Aid to Southeast Asia, a non-governmental organization * American Scientific Affiliation, an organization of Christians in science * American Society of Agronomy * American Society of Anesthesiologists * American Society of Appraisers *American Sociological Association * American Staffing Association * American Standards Association, a former name of the American National Standards Institute * American Statistical Association * American Synesthesia Association * Americans for Safe Access, marijuana law reform group * Association for Social Advancement, microfinance institution, Bangladesh * Association for the Study of Abortion * Association of Scouts of Azerbaijan * Association of Southeast Asia * Australian Society of Authors * Australian Space Agency * Austrian Service Abroad * Autism Society of America * United States Army Security AgencySports
* Agremiação Sportiva Arapiraquense, Brazilian soccer club * Alliance Sport Alsace, French basketball club * Amateur Softball Association, former name of the governing body now known as USA Softball * Amateur Swimming Association, former name of Swim England * American Sailing Association * American Samoa, IOC country code * American Speed Association, motorsports sanctioning body * American Sportscasters Association * Arizona Soccer Association * Athletics South Africa, the national governing body for the sport of athletics in South Africa * Atlético Sport Aviação, Angolan multisports club * United States Adult Soccer AssociationTransportation
* ASA (automobile), Italian marque of automobiles (Autocostruzioni Società per Azioni) * ASA Aluminium Body, Argentinian manufacturer of replicas of sports cars * Aeropuertos y Servicios Auxiliares, Mexican airport operator * African Safari Airways, airline company based in East Africa * Air transport agreement, Air services agreement, bilateral agreement to allow international commercial air transport services between signatories * Atlantic Southeast Airlines, in Atlanta, Georgia * Airline Superintendents Association, of Trinidad & Tobago * Airservices Australia, air traffic management and related services provider for Australia * The International Civil Aviation Organization's code for Alaska AirlinesOther
* ASA, a measure of Film speed#ASA, film speed in photography, later replaced by the ISO standard * Acrylonitrile styrene acrylate, a plastic polymer * Adaptive simulated annealing, optimization algorithm * Cisco ASA (Adaptive Security Appliances) * Allied States of America, a fictional American nation in the television show ''Jericho'' * Allmennaksjeselskap, the designation for a Norwegian public limited company * Anti-Soviet agitation, a criminal offense in the Soviet Union * ASA carriage control characters, a system used for controlling mainframe line printers * District attorney, Assistant state's attorney, a title for attorneys working in the state's attorney's office in the United States * As-salamu alaykum, a greeting in Arabic that means "peace be upon you" * Auditory scene analysis, a proposed model for the basis of auditory perceptionSee also
* Åsa (disambiguation) {{disambiguation