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

Transportation

Aviation

* 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, an US American charter airline (ICAO code BKA) * B4, then-IATA code of

Flyglobespan Flyglobespan was a Scotland, Scottish low-cost airline based in Edinburgh. It operated scheduled services from five airports across Scotland, England and Ireland to destinations in Europe, North America, North Africa and South Africa. Its main ...

, a former British airline * Auster B.4, 1951 British light transport aircraft with rear ramp * Bensen B-4,

Bensen Aircraft The Bensen Aircraft Corporation was established by Dr. Igor Bensen at Raleigh-Durham International Airport in North Carolina in 1952 to develop and market a variety of helicopters and autogyros of Bensen's own design. History Their most succes ...

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 The Keystone B-4 was a biplane bomber aircraft, bomber, built by the Keystone Aircraft company for the United States Army Air Corps. Design and development Originally ordered by the United States Army Air Corps as the LB-13 light bomber. When t ...

, United States biplane bomber * Lohner B.IV, an Austro-Hungarian World War 1 reconnaissance biplane * Pilatus B-4, Swiss glider also designated PC-11.

Locomotives

* 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 PRR may refer to: * Parietal reach region, of the human brain * Pattern recognition receptor, receptors of the innate immune system that identify pathogen-associated molecular patterns * Pennsylvania Railroad (reporting mark), an American railroad ...

, an American

Pennsylvania Railroad The Pennsylvania Railroad ( reporting mark PRR), legal name as the Pennsylvania Railroad Company, also known as the "Pennsy," was an American Class I railroad that was established in 1846 and headquartered in Philadelphia, Pennsylvania. At its ...

steam locomotive * Soo Line B-4 class, an American 0-6-0 steam locomotive *

LB&SCR B4 class } The B4 class were 4-4-0 steam locomotives for express passenger work on the London, Brighton and South Coast Railway. They were designed by R. J. Billinton and were either built at Brighton works 1899–1902 or else by Messrs Sharp, Stewart and ...

, a British tender locomotive class * LNER Class B4, a British class of locomotives

Automotive uses

* Subaru B4, the name under which the

Subaru Legacy The is a mid-size car built by Japanese automobile manufacturer Subaru from 1989 to 2025. The maker's flagship car, it is unique in its class for offering all-wheel drive as a standard feature, and Subaru's traditional boxer engine. The Leg ...

is marketed in Israel * B4 (New York City bus), serving Brooklyn * B4 road (Namibia) *

Bundesstraße 4 The Bundesstraße 4 (abbr. B4) is a German federal highway running in a northwesterly to southerly direction from the state of Schleswig-Holstein to Bavaria. It provides a direct route for motorists traveling between Hamburg and Nuremberg. Th ...

, federal highway in Germany * Alpina B4, a German sports executive car

In the military

* HMS ''B4'', a British B-class submarine of the Royal Navy *

, 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 flight bag can refer to any baggage taken on board a flight, but usually refers to a specific type of document bag carried by pilots and flight crews. Often adorned with an airline logo, at one time the flight bag was a chic fashion accessory. ...

* A level of

vehicle armour Military vehicles are commonly armoured (or armored; American and British English spelling differences#-our, -or, see spelling differences) to withstand the impact of Fragmentation (weaponry), shrapnel, bullets, Shell (projectile), shells, Rocke ...

In science

Leukotriene B4 receptor The leukotriene B4 receptors (BLTRs) include the following two receptor Receptor may refer to: * Sensory receptor, in physiology, any neurite structure that, on receiving environmental stimuli, produces an informative nerve impulse *Receptor (bio ...

and Leukotriene B4 receptor 2, two human genes *

Lipoxin B4 A lipoxin (LX or Lx), an acronym for lipoxygenase interaction product, is a bioactive autacoid metabolite of arachidonic acid made by various cell types. They are categorized as nonclassic eicosanoids and members of the specialized pro-resolving ...

, a lipoxin * Proanthocyanidin B4, a B type proanthocyanidin * Vitamin B4, an alternate name for adenine * A

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 ...

In entertainment

* ''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 ''Babylon 5'' is an American space opera television series created by writer and producer J. Michael Straczynski, under the Babylonian Productions label, in association with Straczynski's Synthetic Worlds Ltd. and Warner Bros. Domestic Telev ...

space station, predecessor to Babylon 5 from the ''Babylon 5'' television series * The Lost City (B4), a ''Dungeons & Dragons'' adventure module

Other uses

* 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 Native Instruments is a German company that develops, manufactures, and supplies music software and hardware for music production, sound design, performance, and DJing. The company's corporate headquarters and main development facilities are lo ...

virtual synthesizer for Hammond organ (B-3) sound emulation * B4-mount, used for professional video cameras such as Betacam * An international standard

paper size Paper size refers to Technical standard, standardized dimensions for sheets of paper used globally in stationery, printing, and technical drawing. Most countries adhere to the ISO 216 standard, which includes the widely recognized A series ( ...

(250×353 mm), defined in ISO 216 * B04,

Alekhine's Defence Alekhine's Defence is a chess opening that begins with the moves: :1. e4 Nf6 Black tempts White's pawns forward to form a broad , with plans to undermine and attack the white structure later in the spirit of hypermodern defence. White's imposi ...

chess code * 1. b4, Sokolsky Opening in chess