ER or Er may refer to:

Places

* English Republic, alternative name for the Commonwealth of England *

Eritrea Eritrea ( ; ti, ኤርትራ, Ertra, ; ar, إرتريا, ʾIritriyā), officially the State of Eritrea, is a country in the Horn of Africa region of Eastern Africa, with its capital and largest city at Asmara. It is bordered by Ethiopia ...

(ISO 3166-2 two letter country code)

United States

* East Rochester, New York * Erie, Pennsylvania

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), 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 Edward VIII (Edward Albert Christian George Andrew Patrick David; 23 June 1894 – 28 May 1972), later known as the Duke of Windsor, was King of the United Kingdom and the Dominions of the British Empire and Emperor of India from 20 January 19 ...

** 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 ''Chico Enterprise-Record'' is the daily newspaper of Chico, California. Also known as the E-R, the newspaper was first published in Bidwell Bar, California as the Butte Record in 1853 and is now part of the MediaNews Group corporation, who ...

'', 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) * Eldorado Reno, a hotel and casino in Reno, Nevada * Eldorado Resorts, a gaming company located in Reno, Nevada * Entre Ríos Railway in Argentina (reporting mark ER) *

Estonian Reform Party The Estonian Reform Party ( et, Eesti Reformierakond) is a liberal political party in Estonia. The party has been led by Kaja Kallas since 2018. It is colloquially known as the "Squirrel Party" ( et, Oravapartei). It was founded in 1994 by Si ...

* United Russia, or ''Yedinaya Rossiya'', a Russian political party

Finance and banking

* ER, abbreviation of

exchange rate In finance, an exchange rate is the rate at which one currency will be exchanged for another currency. Currencies are most commonly national currencies, but may be sub-national as in the case of Hong Kong or supra-national as in the case of ...

* 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 linguistics, a filler, filled pause, hesitation marker or planner is a sound or word that participants in a conversation use to signal that they are pausing to think but are not finished speaking.Juan, Stephen (2010).Why do we say 'um', 'er', ...

in English * Er, alternate spelling for

Yer A yer is either of two letters in Cyrillic alphabets, ъ (ѥръ, ''jerŭ'') and ь (ѥрь, ''jerĭ''). The Glagolitic alphabet used, as respective counterparts, the letters (Ⱏ) and (Ⱐ). They originally represented phonemically the "ult ...

(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 In linguistics, an agent noun (in Latin, ) is a word that is derived from another word denoting an action, and that identifies an entity that does that action. For example, "driver" is an agent noun formed from the verb "drive". Usually, ''derive ...

(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

* Erdős–Rényi model, a model in graph theory

Biology and medicine

* Emergency room, or

emergency department An emergency department (ED), also known as an accident and emergency department (A&E), emergency room (ER), emergency ward (EW) or casualty department, is a medical treatment facility specializing in emergency medicine, the acute care of pati ...

, in a medical facility *

Endoplasmic reticulum The endoplasmic reticulum (ER) is, in essence, the transportation system of the eukaryotic cell, and has many other important functions such as protein folding. It is a type of organelle made up of two subunits – rough endoplasmic reticulum ( ...

, a type of organelle in cell biology *

Er blood group system The Er blood group system consists of five human red blood cell surface antigens, Era, Erb, Er3, Er4 and Er5. The incidences of Era and Er3 are each greater than 99% of the human population, while the incidence of Erb is less than 0.01%. Er4 and E ...

* Equine exertional rhabdomyolysis, a syndrome that damages muscle tissue in horses * Estrogen receptor, a type of protein molecule *

Extraction ratio Extraction ratio is a measure in renal physiology, primarily used to calculate renal plasma flow in order to evaluate renal function. It measures the percentage of the compound entering the kidney that was excreted into the final urine.

, a pharmacokinetic property

Chemistry and physics

\epsilon_r

, a representation for relative static permittivity * Electrorheological (ER) fluid, a type of chemical suspension *

Enantiomeric ratio In stereochemistry, enantiomeric excess (ee) is a measurement of purity used for chiral substances. It reflects the degree to which a sample contains one enantiomer in greater amounts than the other. A racemic mixture has an ee of 0%, while a si ...

, a concept in chemistry * Erbium, symbol Er, a chemical element *

Einstein-Rosen bridge A wormhole ( Einstein-Rosen bridge) is a hypothetical structure connecting disparate points in spacetime, and is based on a special solution of the Einstein field equations. A wormhole can be visualized as a tunnel with two ends at separate p ...

(ER) relativistic wormholes

Computing

.er .er is the country code top-level domain A country code top-level domain (ccTLD) is an Internet The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to ...

, 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

* 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 An emergency procedure is a plan of actions to be conducted in a certain order or manner, in response to a specific class of reasonably foreseeable emergency, a situation that poses an immediate risk to health, life, property, or the Natural enviro ...

related to emergency services * English Reports of the English Courts from 1220 to 1866 * Extended range (military)