sigmoid
/ˈsɪɡ.mɔɪd/
"sigmoid" is a 7-letter English headword indexed on PlainSpell.
The verdict
“sigmoid” is uncommon English (frequency #90,991 among 6,566 “S” headwords), classed as an adjective. The kind of spelling people second-guess.
- #90,991
- frequency rank, English
- 6,566
- “S” headwords
According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - Semi-circular, like the uncial or lunate sigma (similar to English C).
Corpus desk
Index EN-sigmoid · sigmoid · English
sigmoid · rank #90,991 · 0 variants · 0 confusables
- FREQ-RARE #90,991
- LEN-LONG 7 letters
- VOW-3 3 vowels
- CONFUS-0 No pairs
- VAR-0 0 variants
- BOOK-DENSE 6,566
- PHOTO-FINISH signboard
Nearest frequency peer: signboard (+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.
Long-tail ranks near “sigmoid”
Sparse band: bars invert rank so rarer forms read shorter
- shish
shish
9,015 corpus weight
- sifu
sifu
9,012 corpus weight
- sigmoid
sigmoid
9,010 corpus weight
- signboard
signboard
9,009 corpus weight
- skipjack
skipjack
9,007 corpus weight
- slaty
slaty
9,005 corpus weight
What this shows Long-tail view: where “sigmoid” sits against similarly uncommon English ranks.
| Property | Value |
|---|---|
| Headword | sigmoid |
| Language | English |
| Part of speech | Adjective |
| IPA | /ˈsɪɡ.mɔɪd/ |
| Letters | 7 |
| Frequency rank | #90,991 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Long-tail rank of “sigmoid” in English
Rare enough to double-check
sigmoid is uncommon English at frequency #90,991 among 6,566 “S” headwords, classed as anadjective, transcribed /ˈsɪɡ.mɔɪd/. Rarity is why readers land here mid-draft. 4 senses are on record.
Our edit-distance generator produced no likely misspellings for sigmoid, typically a sign the spelling maps closely to how the word sounds. This headword has no recorded confusable partner, since no other headword is close enough in sound or shape to pair with it.
Etymologically, the entry records: Borrowing from Ancient Greek σῑγμοειδής (sīgmoeidḗs, “of the shape of sigma”), from σῖγμᾰ (sîgmă, “sigma”) + -ο- (-o-) + -ειδής (-eidḗs, “-oid, -like”); Equivalent to sigma + -oid. Compare with French sigmoïde. The correct English form is sigmoid, spelled S-I-G-M-O-I-D.
Definition
- 1Semi-circular, like the uncial or lunate sigma (similar to English C).
- 2Curved in two directions, like the letter "S", or the Greek ς (sigma); having a serpentine shape.
- 3Curved in two directions, like the letter "S", or the Greek ς (sigma); having a serpentine shape.
- 4Relating to the sigmoid colon.
Etymology
Borrowing from Ancient Greek σῑγμοειδής (sīgmoeidḗs, “of the shape of sigma”), from σῖγμᾰ (sîgmă, “sigma”) + -ο- (-o-) + -ειδής (-eidḗs, “-oid, -like”); Equivalent to sigma + -oid. Compare with French sigmoïde.
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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Similar English words by spelling shape
Same letter count and similar misspelling depth for "sigmoid", not the corpus desk frequency band.
Same letter count
Frequency-ranked English headwords with 7 letters (nearest by frequency rank).