epsilon
/ɛpˈsaɪ.lən/
"epsilon" is a 7-letter English headword indexed on PlainSpell.
The verdict
“epsilon” is a moderately-common English word, ranked #33,640 in English word frequency and used as a noun.
- #33,640
- frequency rank, English
- 7
- letters
- 10
- tracked misspellings
According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - The fifth letter of the Greek alphabet, ε or Ε, preceded by delta (Δ, δ) and followed by zeta (Ζ, ζ).
| Property | Value |
|---|---|
| Headword | epsilon |
| Language | English |
| Part of speech | Noun |
| IPA | /ɛpˈsaɪ.lən/ |
| Letters | 7 |
| Frequency rank | #33,640 |
| Misspellings tracked | 10 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Where “epsilon” sits in English frequency
Spelling & Dictionary Insight
The English entry for epsilon is 7 letters long, classified as a noun, and transcribed in the International Phonetic Alphabet as /ɛpˈsaɪ.lən/. Corpus data places it at rank #33,640 in overall English word frequency, marking it as uncommon enough that many writers pause before typing it. Wiktionary records 6 distinct senses for this headword, so context determines which meaning a reader should apply.
Our generated misspelling index lists 10 likely wrong-spelling variants for epsilon, with forms such as "epislon", "eppsilon", and "epsillon". Every one of these variants traces to a single-character edit -- an added or dropped letter, a swapped consonant, or a vowel swap -- the kind of slip a spell-checker is built to catch. No confusable counterpart is on file for this word, since its spelling is unusual enough that it doesn't cluster with a lookalike.
Etymologically, the entry records: From Ancient Greek ἒ ψιλόν (è psilón, “simple Ε”). The correct English form is epsilon, spelled E-P-S-I-L-O-N.
Definition
- 1The fifth letter of the Greek alphabet, ε or Ε, preceded by delta (Δ, δ) and followed by zeta (Ζ, ζ).
- 2In IPA, the phonetic symbol ɛ that represents the open-mid front unrounded vowel.
- 3An arbitrarily small quantity.
- 4An arbitrarily small quantity.
- 5Something negligible or insignificant.
- 6The percentage change in an option value with respect to the underlying dividend yield.
Etymology
From Ancient Greek ἒ ψιλόν (è psilón, “simple Ε”).
This word in other languages
Common misspellings
Also misspelled as: epislon,eppsilon,epsillon,epsilno,epsilonn,epsioln,epslion,epssilon,espilon,pesilon
Misspelling Pattern Breakdown
How far each generated variant is from the correct spelling of epsilon - measured in single-character edits (insert, delete, or substitute a letter). Larger bars are easier to catch; one-edit slips are the sneakiest.
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 “epsilon”
The practical upshot for anyone who landed here from a spell-check.
- The one correct English spelling is E-P-S-I-L-O-N - every other letter order is a misspelling in standard orthography.
- Say it as /ɛpˈsaɪ.lən/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
- Browse more English words and confusable pairs in the same reference. English words
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.