B4

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

Transportation

Auster B.4, an unusual 1951 British development of the Auster family of light aircraft
Lohner B.IV, an aircraft
Bensen B-4, a Bensen Aircraft product
Flyglobespan IATA airline designator
B.A.C.H. Flugbetriebs IATA airline designator (ICAO BCF)
Bankair IATA code, ICAO airline designator (BKA)
Fokker F.11, known to its parent company in the Netherlands as the B.IV
2037 Bomber, nicknamed "B-4", in series with "B-3" (the NGB or LRS-B) and "B-2 stealth bomber"
Pilatus B-4, also known as the PC-11 in the Pilatus numbering sequence, an all-metal intermediate glider built by Pilatus Aircraft of Switzerland.

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

A painted B-4 bag

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 United States Air Force/USAAF flight bag
a level of vehicle armour

B4 (music show), an early morning pop promo show on Channel 4 TV
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) is a Dungeons & Dragons adventure module.

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