E2 or E-2 may refer to:

• E2 mechanism, in organic chemistry

In technology: An elimination reaction is a type of organic reaction in which two substituents are removed from a molecule in either a one or two-step mechanism. ... Organic chemistry is a specific discipline within chemistry which involves the scientific study of the structure, properties, composition, reactions, and preparation (by synthesis or by other means) of chemical compounds consisting of primarily carbon and hydrogen, which may contain any number of other elements, including nitrogen, oxygen, halogens as well...

• E2 (cipher), a block cipher submitted to the AES competition by NTT
• E2 (encyclopedia), a collaborative web-based community consisting of a database of interlinked user-submitted written material
• Honda E2, one of the predecessors of Honda's ASIMO robot
• Motorola ROKR E2, a smartphone
• Tungsten E2, a business-class Palm OS-based handheld computer
• Shure E2 (sometimes called E2c) canalphones

In television: In cryptography, E2 is a block cipher which was created in 1998 by NTT and submitted to the AES competition. ... Everything2, or E2 for short, is a collaborative Web-based community consisting of a database of interlinked user-submitted written material. ... Press release photo of the most recent ASIMO model ASIMO ) is a humanoid robot created by Honda Motor Company. ... Motorola ROKR E2 is the successor to the Motorola ROKR E1, a smartphone with iTunes support (depends on distributor). ... The Tungsten E2 is palmOnes replacement model for the Tungsten E. The E2 was released on April 13, 2005. ... Shure Incorporated is a consumer and professional audio electronics corporation. ... Headphones (also known as earphones, stereophones, headsets, or the slang term cans) are a pair of transducers that receive an electrical signal from a media player or receiver and use speakers placed in close proximity to the ears (hence the name earphone) to convert the signal into audible sound waves. ...

• Design e2, a documentary-style television series produced by PBS investigating sustainable living and green design
• "E²" (Enterprise episode), an episode of Star Trek: Enterprise
• MTV e2, a Canadian entertainment news program that airs on MTV Canada

In transportation: design: e2 is a six parts documentary-style television series produced by PBS investigating sustainable living and green design from New York City to China. ... E² is the title of an episode from the third season of the television series Star Trek: Enterprise. ... MTV e2 is a Canadian entertainment news program that airs on MTV Canada and CTV. The show is hosted by Anna Cyzon and it is produced at the Masonic Temple in downtown Toronto. ...

• E-2 Hawkeye, a carrier-based AWACS aircraft of the United States Navy
• E2 Series Shinkansen, new trains built between 1997 and 2005 for Japan's Jōetsu, Tōhoku and Nagano Shinkansen high-speed rail lines
• EMD E2, an early American passenger-train diesel locomotive
• European walking route E2, a 4850km long-distance footpath that runs from Galway in Ireland to France's Mediterranean coast
• HMS E2, an E-class submarine of the Royal Navy
• LB&SCR E2 Class, a class of 0-6-0T steam locomotives designed by Lawson Billington
• Taylor E-2, a small, light and simple utility aircraft
• USS E-2 (SS-25), an E-class submarine of the United States Navy

In other fields: The Grumman E-2 Hawkeye is the United States Navys all-weather, aircraft carrier-based tactical Airborne Early Warning (AEW) aircraft. ... The E2 Series Shinkansen are new trains (construction started in 1997) for Japans Joetsu, Tohoku and Nagano Shinkansen high-speed dedicated rail lines. ... The first E2 set for the City of San Francisco, units SF-1, SF-2 and SF-3, jointly owned by the UP, the C&NW, and the SP. The second E2 set for the City of Los Angeles, units LA-1, LA-2 and LA-3, jointly owned by... Categories: Hiking trails in Europe | Stub ... Length: Beam: 6. ... London, Brighton and South Coast Railway E2 Class was a class of 0-6-0T steam locomotives. ... The Taylor E-2 Cub was originally designed by C. Gilbert Taylor as a small, light and simple utility aircraft. ... USS E-2 (SS-25) was an E-class submarine of the United States Navy. ...

• E-2 South Korean visa, a South Korean language teaching visa
• E2 reaction, a type of organic reaction in which two substituents are removed from a molecule in a one-step mechanism
• London E2, the postcode for Bethnal Green in London
• Private E-2, the paygrade of the rank Private in the U.S. Army

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