# EI

EI or Ei may refer to:

## Arts and media

* "E.I." (song), a single by Nelly
* E/I, a type of children's television programming shown in the United States
* Ei (album), an album by Maija Vilkkumaa
** "Ei" (song), its first single
* Eerie, Indiana, an American television series
* Enrique Iglesias, Spanish pop music singer-songwriter
* Exposure index, the film speed rating of photographic film as exposed

## Businesses and organizations

* Aer Lingus (IATA code EI), the flag airline of Ireland
* The Earth Institute, a collection of research centers at Columbia University
* Education International, a global union federation of teachers' trade unions
* Elektronska Industrija Niš, electronics enterprise based in Niš, Serbia
* Energy Institute, the main professional organization for the energy industry within the UK
* Engineers Ireland, the professional body for engineers and engineering in Ireland
* Enterprise Ireland, is the Irish government organisation responsible for the development and growth of Irish enterprises in world markets.
* Expeditors International, the global logistics and freight forwarding company based out of Seattle, Washington
* The Electronic Intifada, an online publication covering the Israeli-Palestinian conflict from a Palestinian perspective

## Linguistics

* ⟨ei⟩, a digraph found in some Latin alphabets
* The original name of the Greek letter Epsilon
* ɛɪ in the International Phonetic Alphabet (IPA)

## Places

* Ei, Kagoshima, a town located in Ibusuki District, Kagoshima, Japan
* Emerald Isle, North Carolina, a town in Carteret County, North Carolina, United States

## Science, technology, and mathematics

* Ei (prefix symbol), the prefix abbreviation of the binary unit prefix "exbi"
* Earth Interactions, a scientific journal published by the American Meteorological Society, American Geophysical Union, and Association of American Geographers
* Ei Compendex, an engineering bibliographic database
* Electron ionization, an ionization method in which energetic electrons interact with gas phase atoms or molecules to produce ions
* Electronic ignition, a variety of modern ignition system
* Engineering Index, an article index for engineering journals
* Engineer intern, an intermediary step to becoming a Professional Engineer
* Environmental illness (multiple chemical sensitivity), a chronic medical condition characterized by symptoms that the affected person attributes to exposure to low levels of chemicals
* Ionization energy (E$_I$), the energy required to remove one electron from one atom to another
* Equine influenza, the disease caused by strains of Influenza A that are enzootic in horse species
* Exponential integral, a special function defined on the complex plane given the symbol Ei

## Other uses

* Education Index, a United Nations measure of the level of educational development in a country
* Ei (name), a Japanese and Burmese name
* Emotional intelligence, the ability to identify, assess, and control emotions
* Employment insurance, the unemployment benefits system of Canada
* Encyclopaedia of Islam, an encyclopaedia of the academic discipline of Islamic studies
* Enhanced interrogation, a euphemism for torture
* Ex infra, a Latin phrase meaning 'from below'
* Extreme ironing, an extreme sport and a performance art
* Esercito Italiano, Italian language for Italian Army
* Raiden Ei, the Electro Archon in 2020 video game Genshin Impact, who appears as Raiden Shogun