{{wiktionary|e1}} '''E1''', '''E01''', '''E.I''' or '''E-1''' may refer to:
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==Transportation== ===Aircraft=== * Azcárate E-1, a Mexican sesquiplane trainer * Fokker E.I, a German fighter aircraft * Grumman E-1 Tracer, an American airborne early warning aircraft * Hydra Technologies E1 Gavilán, a hand-launched Mexican unmanned electronic surveillance drone * Junkers E.I, the Idflieg designation for the 1916 Junkers J1 monoplane * LVG E.I, a 1915 German two-seat monoplane * NFW E.I, a 1917 German monoplane fighter * Pfalz E.I, a Morane-Saulnier H monoplane built under licence for Germany * Siemens-Schuckert E.I, a 1915 German single seat monoplane * Standard E-1, a 1917 early American Army fighter aircraft
===Automobiles=== * BMW E1, a 1991 and 1993 German electric/hybrid city car concept * BYD e1, a 2019–present Chinese electric city car * Dongfeng Fengguang E1, a 2019–present Chinese electric mini crossover * Haima E1, a 2020–present Chinese electric city car * Roewe E1, a 2012 Chinese electric city car concept later produced as the Roewe E50 * E1, a Mazda E type piston engine * Switch E1, a bus Built by Switch Mobility * Bestune E01, a compact electric crossover
===Submarines=== * HMS ''E1'', an E-class submarine of the Royal Navy * USS ''E-1'' (SS-24), a 1917 E-class submarine of the United States Navy
===Roads=== * European route E1, from Northern Ireland to Spain * E1 European long distance path, a long-distance hiking route from Norway to Italy * London Buses route E1, a transport for London contracted bus route * Tomei Expressway and Meishin Expressway, route E1 in Japan * North–South Expressway Northern Route and New Klang Valley Expressway, route E1 in Malaysia * E1 expressway (Philippines) (North Luzon Expressway, Subic–Clark–Tarlac Expressway, and Tarlac–Pangasinan–La Union Expressway), expressway route in the Philippines * E1 expressway (Pakistan) * E01, Southern Expressway in Sri Lanka
===Trains and locomotives=== * E1 Series Shinkansen, a Japanese high-speed train * Bavarian E I, a German steam engines locomotive model * EMC E1, a diesel locomotive * LB&SCR E1 class, an 1874 British 0-6-0 steam locomotive * NCC Class E1, a Northern Counties Committee Irish steam locomotive * NER Class E1, an 1898 class of small 0-6-0T steam locomotive * PRR E1, an American PRR 4-4-2 steam locomotive * SP&S Class E-1, a 1934 steam locomotives class
==Science and mathematics== ===Biochemistry=== * E1 (HCV), a viral structural protein found in hepatitis C * E1, a unimolecular elimination mechanism in organic chemistry * E1-enzymes, also known as Ubiquitin-activating enzymes, an enzyme which catalyzes the first step in the ubiquitination reaction, which targets a protein for degradation via a proteasome] * E1 regulatory sequence for the insulin gene * Estrone, a hormone * Pyruvate dehydrogenase (E1), the first component enzyme of pyruvate dehydrogenase complex * Acireductone synthase, an enzyme * Haplogroup E1 (Y-DNA), a human Y-chromosome DNA haplogroup
===Mathematics=== * Exponential integral, <math>E_1(z)= \int_1^\infty \frac{e^{-tz}}{t}\, {\rm d}t~</math>, mathematical function * the E1 series (number series) of preferred numbers
===Medicine=== * E1-isoprostane, a type of isoprostane
==Businesses and organizations== * E1 Music, an independent record label in the United States * E1 Corp., a Korean chemical and oil company, member of the LS Group * Entertainment One, an international media company
==Electronics== * Honda E1, a predecessor of the ASIMO humanoid robot * Olympus E-1, a digital single-lens reflex camera
==Places== * E1 (Jerusalem), an area east of Jerusalem in the West Bank * E1 postcode district, London, England, United Kingdom
==Other uses== * E01, ECO code for the closed variation of the Catalan Opening in chess * E01, the Encase Image File Format * E-1 (rank), the pay grade for enlisted ranks of Private, Airman Basic, and Seaman Recruit in the United States Military * E1 grade, a difficulty level in rock climbing * E-1 (rocket engine), a liquid propellant rocket engine * E1 carrier, an E-carrier European telecommunications standard * E1, an AMD CPU from the Bobcat (microarchitecture) family * E1, abbreviation for the Oracle JD Edwards EnterpriseOne software * E1 on Gardiner's sign list, representing the bull * E1 Series (boat racing), an international powerboat racing series
==See also== * List of highways numbered 1 * 1E (disambiguation)
{{Letter-Number Combination Disambiguation}}