ER
ER or Er may refer to:
Arts, entertainment and media
- ER (TV series), a 1994–2009 American medical drama series
- E/R, a 1984–1985 American TV sitcom
- Er, a character in Plato's Myth of Er
- Er, a 2005 album by Nils Petter Molvær
- "ER" (song), a 2012 song by Kanjani Eight
- "ER", a song by Royce da 5'9" featuring Kid Vishis from the 2011 album Success Is Certain
- Chico Enterprise-Record, the daily newspaper of Chico, California, US
Businesses and organizations
- Astar Air Cargo, an American cargo airline, IATA designator ER
- Eastern Railway zone, in India
- Estonian Reform Party
Language
- Er (Cyrillic) (Р р), a letter of the Cyrillic alphabet
- Er (cuneiform), a sign in cuneiform writing
- "er", a filler word in English
- Suffix -er in English:
- added to adjectives or adverbs to form a comparative (e.g., fast to faster)
- added to a noun to indicate resident of, as in New Yorker
- added to a verb to make it an agent noun (e.g., cut to cutter)
- Oxford "-er", used to form words like rugger and footer
- R-colored vowel, usually written as "er" in English
- Erhua, adds er sound to syllables in spoken Mandarin Chinese
People
- Er (biblical person), the eldest son of Judah in the book of Genesis
- Nie Er (1912–1935), Chinese composer
- Elliot Rodger (1991–2014), British-American mass murderer
- ER, a royal cypher representing a monarch whose name begins with E
Science and technology
Biology and medicine
- Emergency room, or emergency department, a medical facility
- Endoplasmic reticulum, a type of organelle in cell biology
- Er blood group system
- Equine exertional rhabdomyolysis, in horses
- Estrogen receptor, a type of protein molecule
- Extraction ratio, in renal physiology
Chemistry and physics
- <math>\varepsilon_r</math>, relative permittivity
- Electrorheological fluid, suspensions of non-conducting but electrically active particles
- Enantiomeric ratio, in chemistry
- Erbium, symbol Er, a chemical element
- Einstein-Rosen bridge, or ER bridge, relativistic wormholes
Computing
- .er, country code top-level domain for Eritrea
- Entity–relationship model, a conceptual representation of data
- Error Resilience, an audio coding method used in MPEG-4 Part 3
Engineering
- Engine room, a compartment of a ship where the machinery for marine propulsion is located.
Other uses
- Eritrea, ISO 3166-2 country code ER
- English Reports of the English Courts from 1220 to 1866