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 , a British Royal Navy B-class submarine , a Spanish Navy B-class submarine , a United States Navy B-class submarine
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 Ceylon Government Railway B3, a steam locomotive class 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 B3, a spur of the B (SEPTA Metro) in Philadelphia, PA, US Bellview Airlines (International Air Transport Association code B3)
Biology and medicine Vitamin B3 (niacin) 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
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) , 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 Big Beautiful Bill, a 2025 omnibus bill proposed by POTUS Donald Trump An ISO 216 international standard that defines paper size B3 the chemical formula for triboracyclopropenyl
See also
BE (disambiguation) 3B (disambiguation) BBB (disambiguation)