ER
ER or Er may refer to:
People
- Er (biblical person), the eldest son of Judah in the biblical book of Genesis
 - Nie Er (1912–1935), Chinese composer
 - Elliot Rodger (July 24, 1991 – May 23, 2014), English-American incel mass shooter
 - A Royal cypher representing a monarch 
- Elizabeth Regina (ER), the royal cypher of Elizabeth I
 - Edward Rex (ER / EVIIR), the royal cypher of Edward VII
 - Edward Rex (ER / EVIIIR), the royal cypher of Edward VIII
 - Elizabeth II Regina (EIIR), the royal cypher of Elizabeth II
 
 
Fictional characters
- Er, a character in Plato's Myth of Er
 
Arts, entertainment and media
Music
- Er, an album by Nils Petter Molvær
 - "ER" (song), a 2012 single by Japanese boy band Kanjani Eight
 - "ER", a song by Royce da 5'9" featuring Kid Vishis from Success Is Certain
 
Periodicals
- Chico Enterprise-Record, the daily newspaper of Chico, California
 
Television
- ER (TV series), a 1994–2009 American television medical drama series
 - E/R, a 1984–1985 American television sitcom
 
Businesses and organizations
- Astar Air Cargo (IATA designator ER)
 - Eastern Railway (India)
 - Entre Ríos Railway in Argentina (reporting mark ER)
 - Estonian Reform Party
 
Finance and banking
- ER, abbreviation of exchange rate
 - ER, abbreviation of expense ratio
 
Language
- Er (Cyrillic) (Р / р), a letter of the Cyrillic alphabet corresponding to the Latin letter "R"
 - Er (cuneiform), a sign in cuneiform writing
 - "er", a filler word in English
 - Er, alternate spelling for Yer (Ъ / ъ), the hard-sign letter of the Cyrillic alphabet
 - Suffix -er 
- -er, a suffix added to adjectives or adverbs to form a comparative (e.g., fast to faster)
 - -er, a suffix added to a noun to indicate resident of, as in New Yorker
 - -er, a suffix added to a verb to make it an agent noun (e.g., cut to cutter)
 - Oxford "-er", a suffix used to form words like rugger and footer
 - Erhua (儿化), rhotacization of spoken syllables in Beijing dialect of Mandarin Chinese with the -er suffix (儿)
 
 
Science and technology
Biology and medicine
- Emergency room, or emergency department, in a medical facility
 - Endoplasmic reticulum, a type of organelle in cell biology
 - Er blood group system
 - Equine exertional rhabdomyolysis, a syndrome that damages muscle tissue in horses
 - Estrogen receptor, a type of protein molecule
 - Extraction ratio, a pharmacokinetic property
 
Chemistry and physics
- , a representation for relative static permittivity
 - Electrorheological (ER) fluid, a type of chemical suspension
 - Enantiomeric ratio, a concept in chemistry
 - Erbium, symbol Er, a chemical element
 - Einstein-Rosen bridge (ER) relativistic wormholes
 
Computing
- .er, country code top-level domain (ccTLD) for Eritrea
 - Entity–relationship model, a conceptual representation of data
 - Error Resilience, an audio coding method used in MPEG-4 Part 3
 
Other uses
- Eritrea (ISO 3166-2 two letter country code)
 - Er., Hebrew abbreviation for 'Eruvin, the second tractate of Moed
 - Earned run, a term in the game of baseball
 - Emergency Response, incident response team or emergency procedure related to emergency services
 - English Reports of the English Courts from 1220 to 1866
 
See also
- ERS (disambiguation)
 - Err (disambiguation)
 - All pages with titles containing ER or ERs
 - All pages with titles containing e-r
 - All pages with titles beginning with ER
 - All pages with titles beginning with er
 - Entre Ríos (disambiguation), several uses
 - Erro (disambiguation)
 - Error (disambiguation)
 - Ur (disambiguation)