B4, B04, B.IV or B-4 may refer to:

• B4, IATA code of BeOnd, an airline based in Malé, Maldives
• B4, IATA code of B.A.C.H. Flugbetrieb, an Austrian charter airline (ICAO code BCF)
• B4, IATA code of Bankair, a US American charter airline (ICAO code BKA)
• B4, then-IATA code of Flyglobespan, a former British airline
• Auster B.4, 1951 British light transport aircraft with rear ramp
• Bensen B-4, Bensen Aircraft autogyro
• Bäumer B IV Sausewind, German 1920s sports aircraft
• Fokker B.IV, parent company's designation for American branch's F.11 seaplane
• Hawker B 4, Swedish designation for Hawker Hart biplane
• Keystone B-4, United States biplane bomber
• Lohner B.IV, an Austro-Hungarian World War 1 reconnaissance biplane
• Pilatus B-4, Swiss glider also designated PC-11.

• Alsace-Lorraine B 4, an Alsace-Lorraine P 1 class steam locomotive
• Bavarian B IV, an 1852 German steam locomotive
• GSR Class B4, a former Cork, Bandon and South Coast Railway steam locomotive of the Great Southern Railways, Ireland
• LSWR B4 class, an 1891 British dock tank locomotive
• PRR B4, an American Pennsylvania Railroad steam locomotive
• Soo Line B-4 class, an American 0-6-0 steam locomotive
• LB&SCR B4 class, a British tender locomotive class
• LNER Class B4, a British class of locomotives

• Subaru B4, the name under which the Subaru Legacy is marketed in Israel
• B4 (New York City bus), serving Brooklyn
• B4 road (Namibia)
• Bundesstraße 4, federal highway in Germany
• Alpina B4, a German sports executive car

• HMS B4, a British B-class submarine of the Royal Navy
• Keystone B-4, a United States Army Air Corps biplane bomber
• SM UB-4, a 1915 German U-boat
• 203-mm howitzer M1931 (B-4, "Stalins Hammer"), a World War II Soviet ordnance piece
• B-4 a US Air Force/USAAF flight bag
• A level of vehicle armour

• Leukotriene B4 receptor and Leukotriene B4 receptor 2, two human genes
• Lipoxin B4, a lipoxin
• Proanthocyanidin B4, a B type proanthocyanidin
• Vitamin B4, an alternate name for adenine
• A stellar classification

• B4 (music show), a defunct British music video show broadcast on Channel 4
• B4 (TV channel), a defunct British music television channel
• B-4 (Star Trek), an android in the Star Trek fictional universe
• Babylon 4 space station, predecessor to Babylon 5 from the Babylon 5 television series
• The Lost City (B4), a Dungeons & Dragons adventure module

• B4 (classification), a parasports classification for visually impaired athletes
• B4 Street Fighter Championships, a 2000 fighting game tournament
• B4 or B4 II, a Native Instruments virtual synthesizer for Hammond organ (B-3) sound emulation
• B4-mount, used for professional video cameras such as Betacam
• An international standard paper size (250×353 mm), defined in ISO 216
• B04, Alekhine's Defence chess code
• 1. b4, Sokolsky Opening in chess

• 4B (disambiguation)
• Before (disambiguation)
• BIV (disambiguation)

Topics referred to by the same term

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