ER
Abbreviation with 10 meanings
| Stands for | Emergency room |
|---|---|
| Meanings | 10 |
| Categories | Medical, Science & Engineering, Geography & Places, Business & Finance, Sports, Law & Legal |
| Also written | Er |
ER has ten meanings. The most common are Emergency room (hospital) and Extended release (pharmacy); it can also stand for Endoplasmic reticulum, Estrogen receptor, Eritrea, Employee relations and Employer, plus 3 more listed below.
Meanings of ER at a glance
| # | ER stands for | Context |
|---|---|---|
| 1 | Emergency room | Medical › Hospital |
| 2 | Extended release | Medical › Pharmacy |
| 3 | Endoplasmic reticulum | Science & Engineering › Biology |
| 4 | Estrogen receptor | Medical › Hematology and Oncology |
| 5 | Eritrea | Geography & Places › Country Code |
| 6 | Employee relations | Business & Finance › Human Resources |
| 7 | Employer | Business & Finance › Human Resources |
| 8 | Earned runs | Sports › Baseball |
| 9 | Erbium | Science & Engineering › Chemical Element |
| 10 | Excerpts of record | Law & Legal › Litigation |
1. Emergency room
Medical · Hospital Abbreviations
Everyday name for a hospital emergency department, used by the public, media and many clinicians. It refers to the same service as ED, providing unscheduled urgent and emergency care around the clock.
Example: Mom took him to the ER after he fell off his bike and hurt his wrist.
Professional organizations prefer "emergency department" because modern departments have many rooms and areas, but ER remains common in speech. The NBC drama "ER" (1994 to 2009) popularized the term. In the UK the equivalent is A&E (accident and emergency).
2. Extended release
Medical · Pharmacy Abbreviations
Formulation that releases its drug slowly over many hours, allowing once- or twice-daily dosing and smoother blood levels than immediate-release versions. "Extended-release" is the standard term the FDA uses in generic names, such as metformin ER or oxycodone ER.
Example: Metformin ER 1,000 mg PO with the evening meal; do not crush.
Crushing or chewing ER products can release the whole dose at once, causing dangerous toxicity, especially with opioids, calcium channel blockers and theophylline. Brand suffixes such as XR, XL, SR, CR, CD and LA all describe extended release in some way, but the technologies differ, so pharmacists do not substitute between them unless they are rated equivalent.
3. Endoplasmic reticulum
Science & Engineering · Biology Abbreviations
Network of membrane-enclosed tubes and sacs extending from the nuclear envelope through the cytoplasm of eukaryotic cells. Rough ER, studded with ribosomes, makes and folds proteins destined for secretion or membranes, while smooth ER synthesizes lipids, detoxifies drugs and stores calcium.
Example: Misfolded proteins accumulating in the ER trigger the unfolded protein response.
Keith Porter, Albert Claude and Ernest Fullam first described the ER in electron micrographs in 1945. In muscle cells a specialized form, the sarcoplasmic reticulum, releases the calcium that triggers contraction. RER and SER are common abbreviations for its rough and smooth forms. In hospitals ER means emergency room.
4. Estrogen receptor
Medical · Hematology and Oncology Abbreviations
Protein inside breast cancer cells that binds estrogen and drives growth; tumors with 1 percent or more of cells staining positive are classified as ER-positive. About 70 to 80 percent of breast cancers are ER-positive and can be treated with hormone (endocrine) therapy.
Example: ER 90%, PR 40%, HER2 negative: adjuvant letrozole for 5 years.
ASCO and the College of American Pathologists define tumors with 1 to 10 percent staining as "ER low positive," which may behave more like ER-negative disease. Endocrine therapies include tamoxifen, aromatase inhibitors such as letrozole and anastrozole, and fulvestrant, often combined with CDK4/6 inhibitors in advanced disease. In hospitals ER usually means emergency room.
5. Eritrea
Geography & Places · Country Code Abbreviations
Eritrea, on the Red Sea, became independent from Ethiopia in 1993 after a 30-year war. Asmara, the capital, is a UNESCO World Heritage Site for its Italian modernist architecture; ERI is the alpha-3 code.
Example: Asmara, ER has some of Africa's best-preserved 1930s architecture.
The alpha-3 code is ERI. ER also means emergency room in American English.
6. Employee relations
Business & Finance · Human Resources Abbreviations
HR specialty that handles workplace conflicts, complaints, investigations, discipline, grievances and policy interpretation, aiming to keep treatment of employees consistent and lawful. Employee relations staff often investigate harassment and misconduct allegations.
Example: The complaint was escalated to ER for a formal investigation.
In the UK, "employee relations" also covers dealings with trade unions and collective consultation. ER specialists document findings carefully because their files may later become evidence in litigation.
7. Employer
Business & Finance · Human Resources Abbreviations
Shorthand for employer in benefits and payroll documents, such as an "ER match" in a 401(k) or "ER-paid" premiums, distinguishing the company's share of a cost from the employee's.
Example: The ER contribution covers 80% of the premium for single coverage.
Benefits summaries typically show EE and ER columns side by side. Outside HR, ER most often means an emergency room.
8. Earned runs
Sports · Baseball Abbreviations
Runs charged to a pitcher that did not result from fielding errors or passed balls. The official scorer reconstructs the inning without the errors to decide which runs are earned.
Example: Box score: 6 IP, 5 H, 3 R, 1 ER, 2 BB, 8 K.
Unearned runs count in the score and the pitcher's runs allowed but not in ERA. When a reliever inherits runners who later score, those runs are charged to the pitcher who put them on base. In medicine ER means emergency room.
9. Erbium (Er)
Science & Engineering · Chemical Element Abbreviations
Erbium (element 68) underpins long-distance internet traffic: erbium-doped fiber amplifiers boost light signals near 1,550 nanometers in undersea and terrestrial optical cables without converting them to electricity. Erbium also tints glass pink and powers Er:YAG lasers for skin resurfacing and dentistry.
Example: Undersea repeaters contain Er-doped fiber amplifiers pumped by 980 nm laser diodes.
Carl Gustaf Mosander separated erbium from yttria in 1843, naming it, like yttrium, terbium and ytterbium, after the quarry village of Ytterby in Sweden. The pink color of erbium oxide makes it a common colorant for glass and cubic zirconia. Erbium fiber amplifiers were developed in the late 1980s and transformed the economics of long-haul optical networks.
10. Excerpts of record
Law & Legal · Litigation Abbreviations
Ninth Circuit's version of an appendix: selected portions of the district court record, such as the notice of appeal, judgment, relevant orders and transcript pages, filed by the appellant with its opening brief. Citations take the form "2-ER-245" for volume 2, page 245.
Example: The magistrate judge's ruling appears at 3-ER-411, and the objection at 3-ER-420.
Required by Ninth Circuit Rule 30-1. The appellee may file supplemental excerpts (SER). Everywhere else ER means emergency room, so the legal sense applies only in Ninth Circuit appellate filings.
Related abbreviations
More hospital abbreviations
- DNV – DNV Healthcare
- DON – Director of nursing
- ECF – Extended care facility
- ED – Emergency department
- EVS – Environmental services
- FQHC – Federally qualified health center
- FSED – Freestanding emergency department
- HAC – Hospital-acquired condition
See all 89 hospital abbreviations →
More pharmacy abbreviations
- DTC – Direct-to-consumer advertising
- DUR – Drug utilization review
- EC – Enteric-coated
- elix – Elixir
- ES – Extra strength
- GITS – Gastrointestinal therapeutic system
- GPO – Group purchasing organization
- gtt – Drip (continuous infusion)
See all 134 pharmacy abbreviations →
This entry is for general education and is not medical or legal advice. Abbreviation use varies between institutions; always confirm in context.