E2, e2, E02, E.II, e or E-2 may refer to:
Science and technology E2 reaction, a type of elimination reaction Honda E2, one of the predecessors of Honda's ASIMO robot E2, a communications channel defined in the E-carrier standard G2 (mathematics) (old name E2 or E2), a group E-2 process, an obsolete film developing method for photographic transparency film
Biology and medicine Ubiquitin-conjugating enzyme, a protein component of proteasome-mediated protein degradation E2 regulatory sequence, for the insulin gene Levuglandin E2, an aldehyde Prostaglandin E2, an abortifacient Prostaglandin E2 receptor, a human gene Iodine-deficiency (ICD-10 code: E02) Estradiol, an estrogen steroid hormone Dihydrolipoyl transacetylase, the second element of the multienzyme pyruvate dehydrogenase complex Acireductone dioxygenase (iron(II)-requiring), an enzyme Haplogroup E2 (Y-DNA), a human Y-chromosome DNA haplogroup
Computing E2 (cipher), a block cipher submitted to the AES competition by NTT Tungsten E2, a business-class Palm OS-based handheld computer Motorola ROKR E2, a smartphone Everything2, a collaborative web-based community consisting of a database of interlinked user-submitted written material
Arts and entertainment E (album), a 2007 album by Eros Ramazzotti
Television "E²", an episode of Star Trek: Enterprise MTV e2, a Canadian entertainment news program that airs on MTV Canada E2 (TV channel), a Turkish TV channel e2 by SKY PerfecTV!, a satellite television service in Japan operated by SKY Perfect
Transport Air Northrop Grumman E-2 Hawkeye, an American carrier-based AWACS aircraft Fokker E.II, a 1915 German single-seat monoplane fighter aircraft Pfalz E.II, a German aircraft powered by the Oberursel U.I engine Taylor E-2, a small, light and simple utility aircraft Embraer E-Jet E2 family, an updated version of the E-jet family Eastman E-2 Sea Rover, a 1920s seaplane Eurowings Europe (former IATA code: E2), an Austrian airline subsidiary of Lufthansa Kampuchea Airlines (former IATA code: E2), a Cambodian airline
Rail E2 Series Shinkansen, a Japanese high-speed train EMC E2, an early American passenger-train diesel locomotive LB&SCR E2 class, a class of 0-6-0T steam locomotives designed by Lawson Billington PRR E2, an American PRR 4-4-2 locomotive CNW Class E-2, a class of 4-6-2 steam locomotives built by the American Locomotive Company in 1923
Roads and footpaths E02 expressway (Sri Lanka), in Sri Lanka E2 European long distance path, a long-distance footpath that runs from Galway in Ireland to France's Mediterranean coast North–South Expressway Southern Route (E2), in Malaysia European route E002, in Azerbaijan and Armenia E2 expressway (Philippines), expressway route in the Philippines San'yō Expressway, Hiroshiwa-Iwakuni Road, Ogori Road and Yamaguchi-Ube Road, numbered as E2 in Japan
Submarines HMS E2, an E-class submarine of the Royal Navy USS E-2, an E-class submarine of the US Navy
Other transport London Buses route E2, England
Other uses E-2 visa, a type of US visa E2, a postcode district in the E postcode area for east London, England Private E-2, a pay grade for the rank of Private in the US Army E2 (nightclub), a nightclub in Chicago, US Eternity II puzzle, a puzzle competition E-II Holdings, Inc., an investment holding company formerly owned by Meshulam Riklis, and later by Carl Icahn E2 grade, an assessment of difficulty in rock climbing
See also E2c, earphones by Shure 2E (disambiguation) EII (disambiguation)