AB, ab, or similar may refer to:
Arts and media
American Bandstand, a music-performance television show Analecta Bollandiana, an academic journal on Christian hagiography Ancienne Belgique, a concert hall in Brussels, Belgium
Business Businesses Manufacturing companies A & B High Performance Firearms, a defunct sporting firearms manufacturer Allen-Bradley, a brand of industrial control products, manufactured by Rockwell Automation Anheuser-Busch, a brewing company
Media companies AB Groupe, a French broadcasting group Activision Blizzard, an American video game holding company American Biograph, a former motion picture company
Transportation companies AB Airlines, a defunct British airline Air Berlin (former IATA airline code AB), a former airline operating 1978–2017 Appenzell Railways (), abbreviated AB Bonza (IATA code AB), an Australian airline
Other companies AB Bank, a commercial bank in Bangladesh Alderson Broaddus University, formerly Alderson-Broaddus College, a private university in West Virginia, US Alfa-Beta Vassilopoulos, a Greek supermarket chain AllianceBernstein (New York Stock Exchange Symbol AB), a US-based asset management firm
Business terminology Akcinė bendrovė, Lithuanian equivalent of an S.A. corporation Aktiebolag, Swedish for "corporation", similar to AG, Ltd or Inc.
Linguistics Abkhaz language (ISO 639-1 language code ab), a Northwest Caucasian language spoken mostly by the Abkhaz people Ab (cuneiform), a written syllable Ab (Semitic), a Semitic word for "father" ab, a Welsh patronymic prefix Āb, a Persian word, derived from Ap (water), the Vedic Sanskti term for water
Occupations and ranks Able seaman, a civilian occupation Able seaman (rank), a naval rank Airman basic, the lowest rank in the US Air Force
Organizations Afrikaner Broederbond, a South African secret society from 1918 to 1994 Aryan Brotherhood, an American gang
Places Āb or Anzab-e Olya, a village in Iran AB postcode area, UK, including Aberdeen, Scotland
AB, the WMO country code of Albania AB, the postal abbreviation and ISO 3166 suffix for Alberta, a province in Canada Air Base, used by the United States Air Force for overseas bases AB, used in vehicle registrations for Aschaffenburg, Germany AB, used in vehicle registrations for the Special Region of Yogyakarta, Indonesia
Science and technology
Chemistry Alabamine, a former name of the element astatine Albite, a feldspar mineral Ammonia borane, a chemical compound Antibonding (a.b.), used to describe the character of orbitals in atomic and molecular electronic structure
Medicine AB blood, a blood type in the ABO blood group system AB toxin, Type III toxin secreted by some pathogenic bacteria Antibody (medical abbreviation) Rectus abdominis muscle (common name abs), a paired stomach muscle
Other uses in science and technology AB (star catalogue) Aggregate base, a kind of material used in construction AB Class amplifier, a classification of electric amplifier Category of abelian groups (Ab), in mathematics ApacheBench, a command line tool for Apache HTTP Server
Religion Ab (Egyptian heart-soul concept), a concept in ancient Egyptian religion Pirkei Avot (), a compilation from the Mishnaic period (abbreviation "Ab.") Aitareya Brahmana, an ancient Indian collection of hymns Ab or Av (month), , fifth in the Hebrew calendar, and eleventh in the Tishri-years Ab () or Aria (month), seventh in the Mandaean calendar
Sport Akademisk Boldklub, a Danish professional football club Argja Bóltfelag, a Faroese association football club Aviron Bayonnais, French rugby union club At bat, in baseball statistics
Transportation
Borneo Airways Limited, IATA airline designator AB (to 1965) NZR Ab class, a New Zealand steam locomotive Armed boarding steamer, used by the UK during World War I Crane ship (AB) (US Navy hull classification symbol AB)
People Ab (given name), a short form of Albert (or occasionally Abraham or Abbott) AB de Villiers (born 1984), South African middle order batsman and wicket-keeper Adrien Broner (born 1989), American Boxer, nicknamed AB Allan Border (born 1955), Australian cricketer, nicknamed A.B. Antonio Brown (born 1988), American football player, nicknamed AB
Other uses AB, a South Australian dish similar to a Halal snack pack Adult baby, a person who practices paraphilic infantilism Bachelor of Arts (Latin: Artium baccalaureus) Assembly Bill, a type of legislation in the US AB (game), a guessing game similar to Mastermind
See also A-flat (disambiguation) ("A"), the musical note, scale, or key Amyloid beta (Aβ), peptides of amino acids that are involved in Alzheimer's disease ΑΒ / αβ / alphabeta (disambiguation) A/B (disambiguation) BA (disambiguation) ABC (disambiguation)