A0

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) note on a standard piano
• A0, a climbing grade
• A00, Irregular chess openings 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 characters
• a₀, the accepted mathematical symbol for the Bohr radius
• Haplogroup A00 and A0; see Y-chromosomal Adam and Haplogroup A (Y-DNA)
• A0, a subdivision in stellar classification
• A0, sometimes written as 0xA0, is the hexadecimal representation of non-breaking space in various character encoding standards
• A0 road (Sri Lanka), an A-Grade road in Sri Lanka
• Bucharest Ring Motorway, The Bucharest Ring Motorway, termed A0

Airplanes and rockets

• A-0, a 1943 Pre-production model of the German Walter HWK 509 liquid-fuel bipropellant rocket engine
• A-0, a 1938 variant of the German Siebel Si 204 transport and trainer aircraft
• He 177 A-0, a pre-production series of the 1942 German Heinkel He 177 heavy bomber
• Hs 126A-0, a variant of the 1937 German Henschel Hs 126 reconnaissance aircraft
• Ju 87 A-0, a variant of the 1936 German Junkers Ju 87 dive bomber aircraft
• Me 210A-0, a pre-production variant of the 1943 German Messerschmitt Me 210 heavy fighter aircraft

Submarine

• Isaac Peral (A-0), a Spanish submarine

See also

• AO (disambiguation)
• 0A (disambiguation)