A4 in Encyclopedia

"A-4 Helldiver", the civil version of the Curtiss Falcon an attack aircraft manufactured by Curtiss Aircraft Company
A-4 Skyhawk, a 1954 attack aircraft manufactured by Douglas Aircraft Company
Breda A.4, a 1926 Italian biplane trainer aircraft
Focke-Wulf A 4, a World War II German Focke-Wulf aircraft
Aggregat-4, the technical name for V-2 ballistic missile
A4, Southern Winds Airlines, the defunct Argentine airline, as its IATA code

Locomotives

Bavarian A IV, a 1852 German steam locomotive model
LNER Class A4, a class of steam locomotives, including the famous Mallard
PRR A4, an American PRR steam locomotive

Other vehicles

A-4, , a Plunger-class submarine of the United States Navy, which was renamed A-4 on 17 November 1911
Arrows A4, a 1982 British racing car
Audi A4, a 1994 Audi luxury compact executive car
HMNZS Kahu (A04), a 1978 Royal New Zealand Navy Moa class inshore patrol vessel
HMS A4, an A-class submarine of the Royal Navy
Prussian A 4, a 1913 German railbus

Roads

List of A4 roads

Other uses

See A (musical note) for A4, in the fourth octave, at Hertz, also known as A-440
A04, Encyclopaedia of Chess Openings code for R ti Opening
A4, a Grade (climbing)
A4, the V-2 rocket, as the actual model number for the German weapon
A4, the code for permission to use specific land or premises for pubs and bars in town and country planning in the UK
A4, the designation for air force headquarters in the NATO continental staff system concerned with logistics
- In the United Kingdom, the A4 Air Logistics branch of the UK Joint Force Air Component Headquarters
A4, the Alternating group acting on four elements
A 4, see List of Swedish regiments for A4, a Swedish designation (4th Artillery Regiment) that has been used by the following units:
- Gotlands artilleriregemente (unknown–1892)
- Norrlands artilleriregemente (1893–1997)
Subfamily A4, a Rhodopsin-like receptors subfamily
A4 Pod, a well-known family of killer whales living in British Columbia coastal waters
A4 paper, a paper size prevalent in many countries (210 297 mm), defined in the ISO 216 international standard
A4, a type of stainless steel, as defined by ISO 3506, equivalent to SAE steel grade 316L
A-004, the sixth and final abort test of the Apollo spacecraft
A4 In the Dungeons of the Slave Lords, a 1981 module for the Dungeons and Dragons role playing game
Biu-Mandara A.4 languages, an Afro-Asiatic family of languages mainly spoken in Cameroon and Nigeria
M16A4, a variant of the American M16 rifle
Route A4 (WMATA), a bus route operated by the Washington Metropolitan Area Transit Authority
Apple A4, microprocessor used in Apple's iPad, iPhone 4, 4th generation iPod Touch and 2nd generation Apple TV.
AMD A4, microprocessor
A4Tech, a company that produces computer peripherals