haplogroup Mathematics Exponential integral, , 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 See also 1E (disambiguation)