A3, A03 or A.III may refer to: *

A3 paper ISO 216 is an International Organization for Standardization, international standard for paper sizes, used around the world except in North America and parts of Latin America. The standard defines the "A", "B" and "C" series of paper sizes, wh ...

, a paper size defined by ISO 216

Biology

* A3 regulatory sequence, a sequence for the insulin gene * Adenosine A₃ receptor, a human gene * Annexin A3, a human gene *

ATC code A03 A03A Drugs for functional gastrointestinal disorders A03AA Chemical synthesis, Synthetic anticholinergics, esters with Tertiary amine, tertiary amino group :A03AA01 Oxyphencyclimine :A03AA03 Camylofin :A03AA04 Mebeverine :A03AA05 Trimebutine :A0 ...

''Drugs for functional gastrointestinal disorders'', a subgroup of the Anatomical Therapeutic Chemical Classification System * Brachydactyly type A3, a disease * British NVC community A3 (Spirodela polyrhiza - Hydrocharis morsus-ranae community), a British Isles plants community *

Gibberellin A3 Gibberellins (GAs) are plant hormones that regulate various developmental processes, including stem elongation, germination, dormancy, flowering, flower development, and leaf and fruit senescence. They are one of the longest-known classes of plan ...

, a plant hormone *

HLA-A3 HLA-A3 (A3) is a human leukocyte antigen ''serotype'' within HLA-A serotype group. The serotype is determined by the antibody recognition of α3 subset of HLA-A α-chains. For A3, the alpha, "A", chain are encoded by the HLA-A allele group and ...

, a Human MHC Serotype HLA-A * Subfamily A3, a

rhodopsin-like receptors Rhodopsin-like receptors are a protein family, family of proteins that comprise the largest group of G protein-coupled receptors. Scope G-protein-coupled receptors, GPCRs, constitute a vast protein family that encompasses a wide range of funct ...

subfamily * Urea transporter A3, a trans-membrane protein

Games

* ''

A3! ''A3!'' (acronym for "Act! Addict! Actors!") is a Japanese mobile game developed by Liber Entertainment. The game was released on January 27, 2017, in Japan. It was given a worldwide English release on October 23, 2019, which later ended servi ...

'', a Japanese video game and multimedia franchise * A3 - Assault on the Aerie of the Slave Lords, a 1981 module for the Dungeons & Dragons fantasy role-playing game *

Alpha Trion This article shows a list of characters from The Transformers (TV series), ''The Transformers'' television series that aired during the debut of the American and Japanese Transformers media franchise from 1984 to 1991. Autobots The Autobots (al ...

, as the former name of this character from the Transformers Series *

Bird's Opening Bird's Opening (or the Dutch Attack) is a chess opening characterised by the move: : 1. f4 Named after 19th century English player Henry Bird, Bird's opening is a standard flank opening. White's strategic ideas involve control of the e5-squa ...

(A03), in chess, by the Encyclopaedia of Chess Openings code

Music

* A3, a

musical note In music, notes are distinct and isolatable sounds that act as the most basic building blocks for nearly all of music. This musical analysis#Discretization, discretization facilitates performance, comprehension, and musical analysis, analysis. No ...

, the A below Middle C *

Alabama 3 Alabama 3 are a British musical group founded in Brixton, Brixton, London, in 1995. Their track "Woke Up This Morning" was used for the opening credits of the TV series ''The Sopranos''. In the United States, the band is known as A3, to avoid ...

, a band known as A3 in the U.S. to avoid confusion with the country group Alabama * A-3, a Yamaha musical instrument product

Sports

A3 (classification) A3 is an amputee sport classification used by the International Sports Organization for the Disabled (ISOD) for people with acquired or congenital amputations. A3 classified sportspeople have both legs amputated below knee. Their amputations im ...

, an amputee sport classification *

A3 Champions Cup A3 Champions Cup (also known as East Asian Champions Cup) was an annual football (soccer) tournament jointly organized by the China PR, Japan and Korea Republic football Association. It began in 2003, involving the league champions of Chinese Supe ...

, a club football tournament also known as the East Asian Champions Cup *

Arrows A3 The Arrows A3 was a Formula One car which the Arrows team used to compete in the 1980 and 1981 Formula One seasons. After the failure of the A2 in the 1979 Formula One season, the A3 was a very conventional design. The A3 featured a short whe ...

, a 1980 racing car * A3, a

climbing grade Many climbing routes have grades for the technical difficulty, and in some cases for the risks, of the route. The first ascensionist can suggest a grade but it will be amended for the ''consensus view'' of subsequent ascents. While many cou ...

Vehicles

A-3 lifeboat The A-3 lifeboat was an airborne lifeboat developed by the EDO Corporation in 1947 for the United States Air Force (USAF) as a successor to the Higgins Industries A-1 lifeboat. The A-3 lifeboat was a key element of "Dumbo" rescue flights of t ...

, a 1947 lifeboat for carrying by the SB-29 Superfortress *

Abrial A-3 Oricou The A-3 ''Oricou'' ( French for ''African vulture'') was a small French touring airplane designed in 1927 by Georges Abrial. It could seat two, and was powered by a 30 kW (40 hp) piston engine. Specifications (A-3 Oricou) See also ...

, a French touring aircraft designed in 1927 *

Audi A3 The Audi A3 is a small family car (C-segment) manufactured and marketed by the German automaker Audi, Audi AG since September 1996. The first two generations of the Audi A3 were based on the Volkswagen Group A platform, while the third and fo ...

, a model of automobile * Aussat (Optus) A3, a 1987 Australian telecommunication satellite * Bavarian A III, an 1851 German steam locomotive model * Chery A3, a compact car * LNER Gresley Classes A1 and A3, a Pacific locomotive class designed by Sir Nigel Gresley * SP&S Class A3, a 1914 steam locomotives class

Weapons and military

* A-3 Falcon, a variant of the Curtiss Falcon, an attack aircraft manufactured by the Curtiss Aircraft Company * A-3 Skywarrior, a strategic bomber manufactured by Douglas Aircraft Company * AUG A3, a variant of the Austrian Steyr AUG rifle * Fokker A.III, a 1915 armed version of the Fokker M.5 aircraft * HMS A3, HMS ''A3'', a British A-class submarine of the Royal Navy * Kampfgeschwader 200, ''Kampfgeschwader'' 200, from its historic ''Geschwaderkennung'' code with the Luftwaffe in World War II * Polaris A-3 missile, an American submarine-launched missile * Wendes Artillery Regiment, a former Swedish Army artillery regiment, by designation * A3, the Continental Staff System, staff designation for air force headquarters staff concerned with operations ** A3 Air Operations Branch, of the Joint Force Air Component Headquarters UK * USS Grampus (SS-4), USS ''Grampus'' (SS-4), a ''Plunger''-class submarine of the United States Navy * Aggregate 3, the 3rd design in the Aggregate family of rockets, precursor to the V-2 rocket, developed by the Germans during World War II

Other uses

* A₃, an example of a root system with numerous physical and geometrical applications * A-3 visa, a document given to employees of A-1 and A-2 Visa Holders who are representing a foreign government inside the U.S. * A3, the code for permission to use specific land or premises for restaurants and cafés in town and country planning in the United Kingdom * A3 roads, in several countries * A-003, the fourth abort test of the Apollo spacecraft * Biu-Mandara A.3 languages, an Afro-Asiatic family of languages spoken in Cameroon and Nigeria * Comet A3 also known as C/2023 A3 (Tsuchinshan–ATLAS) * Cowon A3, an audio media player * Aegean Airlines, by IATA code * Tonga, by aircraft registration code * ARITH-MATIC, as the former name for this programming language * "Agora! Anarchy! Action!", a slogan for Agorism taken from the ''New Libertarian Manifesto'' by Samuel Edward Konkin III * A3 problem solving, a structured problem solving and continuous improvement approach, first employed at Toyota * Samsung Galaxy A3, a smartphone manufactured by Samsung Electronics * Samsung Galaxy A03, a smartphone manufactured by Samsung Electronics * Airbus A³ Vahana, A³ (A-cubed), an Airbus start-up in the Silicon Valley * A3 (TV channel), an Algerian public national television channel also known as Thalitha TV * RED A03, an aircraft diesel engine by German company Red Aviation GmbH * Zeolite A-3, a potassium-type molecular sieve also known as 3A.