RE
Abbreviation with 7 meanings
| Stands for | In re (in the matter of, regarding) |
|---|---|
| Meanings | 7 |
| Categories | Writing & Everyday, Units & Measurements, Business & Finance, Military, Geography & Places, Science & Engineering |
| Also written | Re, re |
RE has seven meanings. The most common are In re (in the matter of, regarding) (Latin) and Reply (email subject prefix) (email and office); it can also stand for Real part, Retained earnings, Royal Engineers, Réunion and Rhenium.
Meanings of RE at a glance
| # | RE stands for | Context |
|---|---|---|
| 1 | In re (in the matter of, regarding) | Writing & Everyday › Latin |
| 2 | Reply (email subject prefix) | Writing & Everyday › Email and Office |
| 3 | Real part | Units & Measurements › Math |
| 4 | Retained earnings | Business & Finance › Accounting |
| 5 | Royal Engineers | Military › Military Unit and Organization |
| 6 | Réunion | Geography & Places › Country Code |
| 7 | Rhenium | Science & Engineering › Chemical Element |
1. In re (in the matter of, regarding) (re)
Writing & Everyday · Latin Abbreviations
Introduces the subject of a memo, letter or notice, meaning "about" or "concerning." In business correspondence it sits on its own line before the body, and in casual writing it can open a sentence about a topic.
Example: Re: your application for the summer internship, we would like to schedule a short interview next week.
Re is the ablative of Latin res, "thing, matter," so it is technically a word rather than an abbreviation and needs no period; a colon usually follows it in headings. Lawyers keep the longer "in re" for case names about a thing or an estate, as in In re Gault. Usage guides advise against "re" in place of "about" in ordinary prose. The "RE:" that email programs add to replies grew out of this usage.
2. Reply (email subject prefix)
Writing & Everyday · Email and Office Abbreviations
Appears as RE: or Re: at the start of an email subject line to show that the message answers an earlier one. Email programs add it automatically when a user clicks Reply or Reply All.
Example: RE: Q3 budget review, attached are the revised figures you asked for in Monday's email.
Most users read it as "reply," but the email standard RFC 5322 describes it as coming from the Latin res, "in the matter of." Outlook writes RE: in capitals, while Gmail and Apple Mail use Re:. Clients in other languages may add local equivalents such as AW: in German or SV: in Swedish and Norwegian, which can stack up in long international threads.
3. Real part (Re)
Units & Measurements · Math Abbreviations
The real component of a complex number: for z = 3 + 4i, Re(z) = 3. It is used in complex analysis, electrical engineering and quantum mechanics.
Example: The physical voltage is Re(V e^(iωt)), the real part of the phasor expression.
Sometimes written with the Fraktur letter ℜ. Engineers represent sinusoidal signals as complex exponentials and take the real part at the end of a calculation. Both Re and Im always return real numbers.
4. Retained earnings
Business & Finance · Accounting Abbreviations
Cumulative net income a company has kept rather than paid out as dividends since its founding, shown within shareholders' equity on the balance sheet. Retained earnings fund growth, debt repayment and future dividends.
Example: Retained earnings, labeled RE on the trial balance, rose by $80 million after a $120 million profit and a $40 million dividend.
A company with accumulated losses shows an "accumulated deficit" instead. Retained earnings are an accounting figure, not a pile of cash; the money may already be invested in assets. Some jurisdictions restrict dividends to distributable reserves, so retained earnings also matter legally.
5. Royal Engineers
Military · Military Unit and Organization Abbreviations
Corps of the British Army responsible for military engineering: building bridges and fortifications, clearing mines and explosives, constructing infrastructure and providing geographic and survey support. Its soldiers are called sappers.
Example: RE units built a temporary bridge after floods washed out the road.
The Corps of Royal Engineers has its headquarters in Chatham, Kent, and traces its history to military engineers of the Norman era. Engineers founded the Royal Engineers football club, which played in the first FA Cup final in 1872.
6. Réunion
Geography & Places · Country Code Abbreviations
French overseas department in the Indian Ocean east of Madagascar, with Saint-Denis as its capital. Piton de la Fournaise, on the island's southeast, is one of the most active volcanoes in the world.
Example: Mail to Saint-Denis, RE travels in the French domestic postal system.
Réunion is an outermost region of the EU and uses the euro. The island has some of the highest rainfall records on Earth. The alpha-3 code is REU.
7. Rhenium (Re)
Science & Engineering · Chemical Element Abbreviations
Jet engine turbine blades are the main destination for rhenium (atomic number 75), one of the rarest elements in Earth's crust and one with an exceptionally high melting point, about 3,186 °C. Platinum-rhenium catalysts also help refineries produce high-octane gasoline.
Example: Single-crystal turbine blades in this engine contain about 3% Re for creep resistance.
Walter Noddack, Ida Tacke and Otto Berg reported rhenium in 1925 in Germany, making it the last stable (non-radioactive) element to be discovered. It is named after the Rhine River (Latin Rhenus). Most rhenium is recovered as a by-product of molybdenum production from copper ores, chiefly in Chile.
Related abbreviations
More Latin abbreviations
- prox. – Proximo mense (next month)
- q.v. – Quod vide (which see)
- QED – Quod erat demonstrandum (which was to be demonstrated)
- R.I.P. – Requiescat in pace (may he or she rest in peace)
- s.l. – Sine loco (without place)
- s.n. – Sine nomine (without name)
- S.P.Q.R. – Senatus Populusque Romanus (the Senate and People of Rome)
- s.v. – Sub verbo (under the word)
See all 53 Latin abbreviations →