B3

B3, B03, B.III or B-3 may refer to:

Military

American bombers

• Keystone B-3, a biplane bomber of the United States Army Air Corps
• Next-Generation Bomber (2018 Bomber), next bomber follow-on to the B-2 stealth bomber program
• Long Range Strike Bomber program, successor program to the 2018 Bomber program
  • Northrop Grumman B-21, a successor aircraft to the B-1 and B-52 bombers

German and Austro-Hungarian aircraft

• AEG B.III, a German reconnaissance aircraft
• Albatros B.III, a German Idflieg B-class designation aircraft
• Aviatik B.III, a 1916 Austro-Hungarian reconnaissance aircraft
• Euler B.III, a German Idflieg B-class designation aircraft
• Fokker B.III (disambiguation), two aircraft models
• Halberstadt B.III, a German Idflieg B-class designation aircraft
• Kampfgeschwader 54, from its historic Geschwaderkennung code with the Luftwaffe in World War II
• Lohner B.III
• LVG B.III, a 1910s German two-seat trainer biplane

Submarines

• USS B-3 (SS-12), a United States Navy submarine
• HMS B3, a British B class submarine of the Royal Navy

Civilian transportation

Roads

• B3 road (Kenya)
• B3 road (Namibia)
• Bundesstraße 3, a German national highway

Trains

• Alsace-Lorraine B 3, an Alsace-Lorraine P 1 class steam locomotive
• Bavarian B III, an 1852 German steam locomotive model
• NCC Class B3, an 1890 Irish 4-4-0 passenger steam locomotive
• NSB B3 (Class 3), Norwegian railway carriages
• LNER Class B3, a British locomotive class

Other

• B3 (New York City bus) serving Brooklyn
• Bellview Airlines (International Air Transport Association code B3)

Biology and medicine

• B3 (classification), a medical-based Paralympic disability sport classification for blind sport
• B3 domain, a highly conserved plant DNA-binding domain
• Procyanidin B3, a plant phenolic compound
• ATC code B03 Antianemic preparations, a subgroup of the Anatomical Therapeutic Chemical Classification System
• Prodelphinidin B3, a plant phenolic compound
• Vitamin B₃ (niacin)

Computing

• A TCSEC security class in the Trusted Computer System Evaluation Criteria
• "B3 Coin" a cryptocurrency

Engines

• A type of four-cylinder Mazda B engine
• Benz B.III, an engine powering the 1914 Friedrichshafen FF.33 German aircraft

Music

• B3 (band), an American boy band most popular in Germany
• B3 (EP), a 2012 EP by alternative rock band Placebo
• Hammond B-3, an electric organ

Other uses

• B3 (stock exchange)
• $B_{3}^{I}$, the Bochvar logic in calculus
• B03, Alekhine's Defence chess code
• B3: Battle by the Bay, a 1996 Street Fighter tournament
• B3 oil field, an oil and gas field in the Baltic sea
• Model B3 chair, a 1925 German Wassili designer chair
• A subclass of B-class stars in stellar classification
• a permission code for Town and country planning in the United Kingdom
• An ISO 216 international standard that defines paper size
• B₃ the chemical formula for triboracyclopropenyl