A0, A-0, A₀, or a₀ may refer to: * 101 A0 and 103 A0, two versions of the German Heinkel Tourist moped * A0 paper size, an international ISO 216 standard paper size (841 × 1189 mm), which results in an area very close to 1 m² * A0 highway (Zimbabwe), a highway which orbits Zimbabwe * A0, the lowest

A (musical note) A is a musical note equivalent to 440 Hz in typical A440 tuning. It is the sixth note of La and the tenth semitone of the fixed-do solfège. Its enharmonic equivalents are B (B double-flat) and G (G double-sharp). "A" is generally used a ...

note on a standard piano * A0, 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 ...

* A00,

Irregular chess opening In chess, an irregular opening is an opening considered unusual or unorthodox. In the early 19th century the term was used for any opening not beginning with 1.e4 e5 (the Open Game) or 1.d4 d5 (the Closed Game). As opening theory has developed ...

s code in the Encyclopaedia of Chess Openings * A00, an unofficial paper size twice the size of A0 paper size * A-0 Geyser, a geyser in Yellowstone National Park * A-0 System, an early compiler related tool developed for electronic computers * L'Avion, IATA airline designator for the French airline * Characters of type A₀, an older term for algebraic

Hecke character In number theory, a Hecke character is a generalisation of a Dirichlet character, introduced by Erich Hecke to construct a class of ''L''-functions larger than Dirichlet ''L''-functions, and a natural setting for the Dedekind zeta-functions and ...

s * ''a''₀, the accepted mathematical symbol for the

Bohr radius The Bohr radius () is a physical constant, approximately equal to the most probable distance between the nucleus and the electron in a hydrogen atom in its ground state. It is named after Niels Bohr, due to its role in the Bohr model of an at ...

* Haplogroup A00 and A0; see Y-chromosomal Adam and

Haplogroup A (Y-DNA) Haplogroup A is a human Y-chromosome DNA haplogroup, which includes all living human Y chromosomes. Bearers of extant sub-clades of haplogroup A are almost exclusively found in Africa (or among the African diaspora), in contrast with haplogroup ...

* A0, a subdivision in

stellar classification In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction gratin ...

* A0, sometimes written as 0xA0, is the hexadecimal representation of

non-breaking space In word processing and digital typesetting, a non-breaking space (), also called NBSP, required space, hard space, or fixed space ...

in various character encoding standards *

A0 road (Sri Lanka) The A0 is an List of A-Grade highways in Sri Lanka, A-Grade road in Sri Lanka. It connects Kollupitiya and Sri Jayawardenepura, the nation's capital. The highway passes through Rajagiriya. References

{{SriLanka-road-stub Highways in Sri ...

, an A-Grade road in Sri Lanka *

Bucharest Ring Motorway The Bucharest Ring Motorway (or the Bucharest Belt Motorway, ), termed A0, is a motorway ring in construction around the city of Bucharest, the capital of Romania. It is intended to be the outer ring of the existing Bucharest Ring Road. It is ...

, The Bucharest Ring Motorway, termed A0

Airplanes and rockets

* A-0, a 1943 Pre-production model of the German

Walter HWK 509 The Walter HWK 109-509 was a German liquid-fuel bipropellant rocket engine that powered the Messerschmitt Me 163 Komet and Bachem Ba 349 aircraft. It was produced by Hellmuth Walter Kommanditgesellschaft (HWK) commencing in 1943, with licensed p ...

liquid-fuel bipropellant rocket engine * A-0, a 1938 variant of the German

Siebel Si 204 The Siebel Si 204 is a small twin-engined transport and trainer aircraft developed in World War II. It was based on the Siebel Fh 104 Hallore. Originally designed in response to a German Ministry of Aviation (Nazi Germany), Ministry of Aviation ...

transport and trainer aircraft * He 177 A-0, a pre-production series of the 1942 German

Heinkel He 177 The Heinkel He 177 ''Greif'' (Griffin) was a long-range heavy bomber flown by the ''Luftwaffe'' during World War II. The introduction of the He 177 to combat operations was significantly delayed by problems both with the development of its ...

heavy bomber * Hs 126A-0, a variant of the 1937 German

Henschel Hs 126 The Henschel Hs 126 was a twin-seat parasol wing reconnaissance and observation aircraft designed and produced by the German aircraft manufacturer Henschel. The Hs 126 that was derived from the Henschel Hs 122. The pilot was seated in a pro ...

reconnaissance aircraft * Ju 87 A-0, a variant of the 1936 German

Junkers Ju 87 The Junkers Ju 87, popularly known as the "Stuka", is a German dive bomber and ground-attack aircraft. Designed by Hermann Pohlmann, it first flew in 1935. The Ju 87 made its combat debut in 1937 with the Luftwaffe's Condor Legion during the ...

dive bomber aircraft * Me 210A-0, a pre-production variant of the 1943 German

Messerschmitt Me 210 The Messerschmitt Me 210 was a German heavy fighter and ground-attack aircraft of World War II. Design started before the war, as a replacement for the Bf 110. The first examples were ready in 1939, but they proved to have unacceptably poor f ...

heavy fighter aircraft

Submarine

* ''

Isaac Peral Isaac Peral y Caballero (1 June 1851, in Cartagena – 22 May 1895, in Berlin), was a Spanish engineer, naval officer, and designer of the submarine . He joined the Spanish Navy in 1866, and developed the first electric-powered submarine which ...

'' (A-0), a Spanish submarine

Airplanes and rockets

Submarine

See also