ER

• English Republic, alternative name for the Commonwealth of England
• Eritrea (ISO 3166-2 two letter country code)

United States

• East Rochester, New York
• Erie, Pennsylvania

• 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

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

• 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
• United Russia, or Yedinaya Rossiya, a Russian political party

• ER, abbreviation of exchange rate
• ER, abbreviation of expense ratio

• 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)

• Erdős–Rényi model, a model in graph theory

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

• ${\displaystyle \epsilon _{r}}$ , 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

• 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

Search for "er"  or "e-r" on Wikipedia.

• 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)