ER

__NOTOC__Er or ER may refer to:

Medicine

* Emergency room, a department of a hospital used for quick and needed medical attention
* Estrogen receptor, a member of the nuclear hormone family of intracellular receptor

Television

* "ER" (TV series), a 1994–2009 NBC medical drama
* "E/R", a 1984–1985 CBS sitcom

cience and computing

* Engineer, a lawful holder of a degree in engineering
* Endoplasmic reticulum, a type of organelle in cell biology
* Estrogen receptor, a type of receptor in biochemistry
* Equine Exertional Rhabdomyolysis, a disease found in horses
* Erbium, a chemical element
* Entity-relationship model or diagram, a conceptual data model used in software engineering and database design
* Relative static permittivity, a concept in chemistry represented as $epsilon\_r$

Language

* Er (Cyrillic), a letter in the Cyrillic alphabet
* The suffix -er
* A filler word used in dialogue displaying uncertainty
* Third person nominative pronoun in German

Other meanings

* Er (Biblical name)
* ER (Extended Range), a term for missiles or aircraft
* Myth of Er, an analogy in Plato's "The Republic"
* Eesti Rahvusringhääling, a public broadcasting organization in Estonia
* Earned run, a concept in the game of baseball
* Evidential Reasoning Approach, a concept in Decision Theory
* United Russia, a political party
* Chico Enterprise-Record, a daily newspaper
* Eritrea, an African country (ER ISO 3166-1 alpha-2 code)
* Astar Air Cargo, an airline (ER IATA code)
* Eduardus Rex, Latin initials used by King Edward I through VII
* Elizabeth Regina, initials used by Queen Elizabeth II (only "Regina" is in Latin)