A2

A2, A02, A002, A², A.II or A-2 may refer to:

Biology and medicine

 * British NVC community A2 (Lemna minor community), a plant community
 * A2, the second anal vein in the Comstock-Needham system of insect wing segment naming

Genes and proteins

 * A-box 2 of insulin gene
 * HLA-A2, a human MHC HLA-A serotype gene
 * Ectodysplasin A2 receptor, a protein that in humans is encoded by the EDA2R gene
 * Alpha-2 adrenergic receptor
 * Annexin A2, a protein
 * Apolipoprotein A-II, a protein
 * Phospholipase A2, an enzyme
 * Prokaryotic phospholipase A2, an enzyme
 * Hemoglobin A2, a protein
 * Proanthocyanidin A2, an A type proanthocyanidin
 * Urea transporter A2, a protein
 * A2, a variant of blood groups alleles A in the ABO blood group system
 * A2, a subfamily of rhodopsin-like receptors

Medicine

 * ATC code A02 Drugs for acid related disorders, a subgroup of the Anatomical Therapeutic Chemical Classification System
 * Brachydactyly type A2, a disease
 * Noradrenergic cell group A2

Computing

 * A-2 (programming language), a follow-on to the A-0 System used on UNIVAC I
 * A2 (operating system), software to run a computer

Electronics

 * DiMAGE A2, a digital camera produced by Minolta
 * IBM A2, an IBM processor used in its supercomputers
 * Cowon A2, a portable multimedia player from Cowon

Gaming

 * A2 Racer, a racing computer game series
 * A2 Secret of the Slavers Stockade, a module in the Scourge of the Slave Lords series for Dungeons & Dragons
 * Final Fantasy Tactics A2: Grimoire of the Rift

Language

 * Biu-Mandara A.2 languages, an Afro-Asiatic family of languages spoken in Nigeria
 * A2, a second language level in the IB Group 2 subjects
 * A2, a level in the Common European Framework of Reference for Languages

Military

 * A-2 jacket, a leather flight jacket
 * A2, the military staff designation in the continental staff system for air force headquarters staff concerned with intelligence and security
 * A 2, Göta Artillery Regiment designation, a former Swedish Army artillery regiment

Music

 * A due, a musical term often abbreviated to a2
 * A2, a rock band that performed the song "Chosen One" in the video game Shadow the Hedgehog

Sport

 * A2 (classification), an amputee sport classification
 * HEBA A2, a Greek basketball league
 * A2 volleyball league (Portugal)
 * A2 women's volleyball league (Portugal)
 * A2, an Italian Baseball League
 * A2, an Italian Volleyball League
 * A2, a grade in climbing

Television

 * A2 (remote television production), a person who manages audio equipment
 * A2 Stereo or Zweikanalton, a television broadcasting system
 * A2 Teema, a panel discussion episode of Ajankohtainen kakkonen, a Finnish television series
 * A2, common abbreviation of Antenne 2, former name (1975–1992) of French national television station France 2

Air

 * A-2 Savage or AJ Savage, an aircraft
 * Abrial A-2 Vautour, a French sailplane built in 1925
 * Antonov A-2, a Soviet glider
 * Breda A.2, a 1921 Italian aircraft
 * Fokker A.II, a German aircraft
 * Nikol A-2, 1939 a prototype of a Polish amphibious flying boat
 * Pfalz A.II, a German Idflieg A-class designation aircraft
 * Reaction Engines A2, a design study for a hypersonic airliner under development
 * Cielos Airlines's IATA code
 * A-2, United States Navy alphanumeric code for the North American AJ Savage carrier-launched bomber
 * A2, a Botswana aircraft registration code

Rail

 * Bavarian A II, an 1847 German steam locomotive model
 * LNER Class A2, a class of steam locomotives
 * LNER Peppercorn Class A2, a class of steam locomotives
 * LNER Thompson Class A2, 3 classes of Pacific locomotives
 * Milwaukee Road class A2, a 1901 4-4-2 type steam locomotive
 * SP&S Class A2, an 1887 steam locomotives class
 * Victorian Railways A2 class, a 1907 Australian steam locomotive
 * PRR A2, a Pennsylvania Railroad locomotive classification
 * Prussian A 2, a Prussian railbus model

Road

 * List of A2 roads
 * Anadol A2, a 1970 Turkish car
 * Arrows A2, a 1979 British racing car
 * Audi A2, a 1999 automobile
 * Merzario A2, see template:F1 cars 1979
 * Route A2 (WMATA), a bus route operated by the Washington Metropolitan Area Transit Authority
 * Audi Quattro A2, a 1984 rally car evolution of the Audi Quattro

Sea

 * HMS A2, a Royal Navy A-class submarine
 * Type A2 submarine, a submarine of the Imperial Japanese Navy during World War II
 * T2-SE-A2, a type of oil tanker constructed and produced in large quantities in the United States during World War II
 * Sea Area A2, as defined under the GMDSS system

Space

 * Saturn A-2, a 1959 American rocket
 * A-002, the third abort test of the Apollo spacecraft
 * Aussat (Optus) A2, a 1985 Australian satellite

Tanks

 * M1A2, a version of the American M1 Abrams tank
 * M60A2, a version of the American M60 Patton tank

Weapons

 * A2 (rocket), a German rocket design (1934)
 * AUG A2 Commando, a variant of the Austrian Steyr AUG rifle
 * M16A2 rifle, a variant of the M16 rifle of the United States Army
 * AR-15A2, a variant of the Colt AR-15 rifle
 * M16A2 mine, a variant of the M16 mine of the United States Army
 * Polaris A-2, a variant of the Polaris missile of the United States Navy

Other uses

 * A2 (theater), a person who manages audio equipment
 * DIN4102 A2, a flammability rating for materials ~98% noncombustible
 * A2-level, an education qualification in England, Wales and Northern Ireland
 * A2 milk, a trademark of the A2 Corporation
 * Radio Station A2, a radio station in Lithuania
 * A-2 tool steel, an air-hardening SAE grade of tool steel
 * A-2 visa, a document given to officials representing a foreign government inside the United States of America
 * Agence de l'innovation industrielle (AII), a French governmental agency for technological projects
 * Ann Arbor, Michigan, often referred to as A2 or A2
 * Bird's Opening's Encyclopaedia of Chess Openings code
 * A2, an international standard paper size
 * A2 or SAE 304, a grade of stainless steel for fasteners
 * A2, a UK Town and Country Planning use class
 * A II, a painting by László Moholy-Nagy, painted in 1924
 * Sea Area A2, a GMDSS system area
 * YoRHa Type A No. 2, or A2, a character from the video game Nier: Automata