RER
"rer" is a 3-letter English headword indexed on PlainSpell.
The verdict
“RER” is uncommon English (frequency #58,975 among 21,470 “R” headwords), classed as a noun. The kind of spelling people second-guess.
- #58,975
- frequency rank, English
- 21,470
- “R” headwords
According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - A type of railway system that generally runs from suburbs or satellite towns into a city centre, with a central tunnel or overground corridor with higher speeds and more widely spread stations than...
| Property | Value |
|---|---|
| Headword | RER |
| Language | English |
| Part of speech | Noun |
| Letters | 3 |
| Frequency rank | #58,975 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Where “RER” sits in English frequency
Rare enough to double-check
RER is uncommon English at frequency #58,975 among 21,470 “R” headwords, classed as anoun. Rarity is why readers land here mid-draft. Gloss: "A type of railway system that generally runs from suburbs or satellite towns into a city centre, with a central tunnel or overground corridor with higher speeds and more widely spread stations than...".
Zero misspellings are on record for RER in our index, which points to an orthography that plays by predictable English rules. It is not paired with a close-neighbour confusable in our dataset, since no other headword is close enough in sound or shape to pair with it.
Etymologically, the entry records: From French RER, often reinterpreted as "Regional Express Rail". The correct English form is RER, spelled R-E-R.
Definition
- 1A type of railway system that generally runs from suburbs or satellite towns into a city centre, with a central tunnel or overground corridor with higher speeds and more widely spread stations than a subway or metro.
Etymology
From French RER, often reinterpreted as "Regional Express Rail".
Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA); frequency ordering uses the FrequencyWords open word-frequency list (2018 English corpus, MIT). See the methodology for how each field is sourced and updated.
Frequently Asked Questions
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Using “RER”
The practical upshot for anyone who landed here from a spell-check.
- The one correct English spelling is R-E-R - every other letter order is a misspelling in standard orthography.
- Browse more English words and confusable pairs in the same reference. English words
Other uncommon English words near this rank
Data Source
Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.