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 (EI), 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
 * 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 Shogun, real name Raiden Ei, a playable character from Genshin Impact