View source for ER

{{wiktionary|er|Er|ER|-er|'er|er-}}

'''ER''' or '''Er''' may refer to:

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== 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 / E<small>VII</small>R), the royal cypher of [[Edward VII]]
** Edward Rex (ER / E<small>VIII</small>R), the royal cypher of [[Edward VIII]]
** Elizabeth II Regina (E<small>II</small>R), 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)|"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)|''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'''&nbsp;/&nbsp;'''р'''), a letter of the Cyrillic alphabet corresponding to the Latin letter "R"
* [[Er (cuneiform)]], a sign in cuneiform writing
* "er", a [[filler (linguistics)|filler word]] in English
* Er, alternate spelling for [[Yer]] ('''Ъ'''&nbsp;/&nbsp;'''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 (disambiguation)|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 ===

* <math>\epsilon_r</math>, a representation for [[relative static permittivity]]
* [[Electrorheological fluid|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 ==
{{Canned search|er|e-r}}

* [[ERS (disambiguation)]]
* [[Err (disambiguation)]]
* {{in title|plural=yes}}
* {{in title|e-r}}
* {{lookfrom}}
* {{lookfrom|er}}
* [[Entre Ríos (disambiguation)]], several uses
* [[Erro (disambiguation)]]
* [[Error (disambiguation)]]
* [[Ur (disambiguation)]]

{{Disambiguation-cleanup|date=February 2025}}