sigma
/ˈsɪɡmə/
"sigma" is a 5-letter English headword indexed on PlainSpell.
The verdict
“sigma” has 7 generated spelling variants in the English index at frequency #14,835. The variants make it a useful spelling check.
- #14,835
- frequency rank, English
- 6,566
- “S” headwords
- 7
- tracked misspellings
- 20
- confusable pairs
According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - The eighteenth letter of the Classical and Modern Greek alphabets (Σ, σ), the twentieth letter of Old and Ancient.
Corpus desk
Index EN-sigma · sigma · English
sigma · rank #14,835 · 7 variants · 20 confusables
- FREQ-MID #14,835
- LEN-MID 5 letters
- VOW-2 2 vowels
- CONFUS-HIGH 20 pairs
- VAR-MID 7 variants
- BOOK-DENSE 6,566
- PHOTO-FINISH shootout
Nearest frequency peer: shootout (-1 rank slots)
Read with this headword: Spelling guide for this pattern
Desk codes from Wiktionary headword shape, FrequencyWords rank tier, confusable-pair count, generated misspelling depth, letter-cohort book size, and photo-finish peer. Not a difficulty grade.
Rank peers near misspelling magnet “sigma”
Same rarity band: useful when a typo lands on a peer headword
- Salisbury
Salisbury
85,171 corpus weight
- scrapped
scrapped
85,169 corpus weight
- seasoned
seasoned
85,168 corpus weight
- shootout
shootout
85,167 corpus weight
- sigma
sigma
85,166 corpus weight
- SK
SK
85,164 corpus weight
What this shows “sigma” sits among these FrequencyWords peers; misspelling depth is tracked separately in the edit-distance chart.
Visual similarity to commonly confused words
How many letter changes separate each confused pair (Levenshtein distance, normalized).
Source: PlainSpell confusable corpus (Wiktionary, CC BY-SA).
| Property | Value |
|---|---|
| Headword | sigma |
| Language | English |
| Part of speech | Noun |
| IPA | /ˈsɪɡmə/ |
| Letters | 5 |
| Frequency rank | #14,835 |
| Misspellings tracked | 7 |
| Confusable pairs | 20 |
| Source | Wiktionary (kaikki.org) |
Frequency seat of misspelling magnet “sigma”
A misspelling magnet
The generator records 7 spelling variants around sigma (IPA /ˈsɪɡmə/), anoun. Corpus frequency is #14,835 among 6,566 “S” headwords. Wiktionary lists 4 senses, so context still picks the gloss.
Our generated misspelling index lists 7 likely wrong-spelling variants for sigma, with forms such as "isgma", "sgima", and "sigam". Each of these forms differs from the correct spelling by one small edit: a doubled letter, a dropped silent letter, or a substituted vowel. It also participates in 20 confusable-pair relationships, "SIM", "SMA", "sign", and more, since the words sound or look close enough that writers reach for the wrong one mid-sentence.
Etymologically, the entry records: From Ancient Greek σῖγμα (sîgma), probably from the root σῑγ- (sīg-) as seen in σίζω (sízō, “to hiss”) + -μα (-ma, nominal suffix). The correct English form is sigma, spelled S-I-G-M-A.
Definition
- 1The eighteenth letter of the Classical and Modern Greek alphabets (Σ, σ), the twentieth letter of Old and Ancient.
- 2The symbol Σ, used to indicate summation of a set or series.
- 3The symbol σ, used to indicate one standard deviation from the mean, particularly in a normal distribution.
- 4A sigma male (a self-reliant and assertive male).
Recorded use
Wiktionary examplesThese source excerpts show how sigma appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.
Their names, which are expressive of some bodily or mental excellence, all end with the same letter---the letter which is called San by the Dorians, and Sigma by the Ionians.
2011, Paul Rincon, (bbc.co.uk) LHC: Higgs boson 'may have been glimpsed' None of the spikes seen by the experiments is at much more than the "two sigma" level of certainty. A level of "five sigma" is required to claim a discovery, meaning there is less than a one in a million chance the data spike is down to a statistical fluke.
Etymology
From Ancient Greek σῖγμα (sîgma), probably from the root σῑγ- (sīg-) as seen in σίζω (sízō, “to hiss”) + -μα (-ma, nominal suffix).
This word in other languages
Common misspellings
Also misspelled as:
- isgma
- sgima
- sigam
- siggma
- sigmma
- simga
- ssigma
Misspelling Pattern Breakdown
How far each generated variant is from the correct spelling of sigma - counted as single-character edits (an insertion, a deletion, or a substituted letter). The larger the bar, the easier the typo is to spot; one-edit slips are the ones that sneak past readers.
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
How do you spell "sigma"?
What does "sigma" mean?
What words are commonly confused with "sigma"?
How do you pronounce "sigma"?
What is the origin of the word "sigma"?
Is PlainSpell free to use?
Similar English words by spelling shape
Same letter count and similar misspelling depth for "sigma", not the corpus desk frequency band.
Same letter count
Frequency-ranked English headwords with 5 letters (nearest by frequency rank).
Similar misspelling depth
Headwords with a similar count of attested misspellings (7 here; floor ≥5).