sex

/sɛks/

//sɛks// noun

"sex" is a 3-letter English headword indexed on PlainSpell.

The verdict

“sex” is in the everyday core of English, ranked #611 in English word frequency and used as a noun.

#611
frequency rank, English
3
letters
20
confusable pairs

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - A category into which sexually-reproducing organisms are divided on the basis of their reproductive roles in their species; the system of such categories, which can differ by organism or by taxonom...

Visual similarity to commonly confused words

How many letter changes separate each confused pair (Levenshtein distance, normalized).

sex vs so
33% similar
sex vs SI
0% similar
sex vs SS
0% similar

Source: PlainSpell confusable corpus (Wiktionary, CC BY-SA).

Key facts for sex
PropertyValue
Headwordsex
LanguageEnglish
Part of speechNoun
IPA/sɛks/
Letters3
Frequency rank#611
Misspellings tracked0
Confusable pairs20
SourceWiktionary (kaikki.org)

Where “sex” sits in English frequency

Every-word frequency runs from the handful of words we use constantly (left) to the long tail used once in a blue moon (right). sex lands here:

#1#100#1K#10K#100K
← used constantlyrarely used →

Scale is logarithmic (each tick is 10× rarer). Source: FrequencyWords open word-frequency list.

Spelling & Dictionary Insight

The English entry for sex is 3 letters long, classified as a noun, and transcribed in the International Phonetic Alphabet as /sɛks/. Corpus data places it at rank #611 in overall English word frequency, putting it firmly in the everyday core of the language. Wiktionary records 7 distinct senses for this headword, so context determines which meaning a reader should apply.

Our edit-distance generator produced no likely misspellings for sex, since its letter pattern doesn't lend itself to common typo substitutions. It also participates in 20 confusable-pair relationships, "so", "SI", "SS", and more, where similar look or sound leads writers to substitute one word for another in context.

Etymologically, the entry records: Etymology tree Proto-Indo-European *sek-der. Proto-Indo-European *séksusder. Proto-Italic *seksus Latin sexusder. Old French sexeder. Middle English sexe English sex From Middle English sexe (“sex [distinction between male and female] and gender”), from Old… The correct English form is sex, spelled S-E-X.

Definition

  1. 1
    A category into which sexually-reproducing organisms are divided on the basis of their reproductive roles in their species; the system of such categories, which can differ by organism or by taxonomic branch.
  2. 2
    Another category, especially of humans and especially based on sexuality or gender roles.
  3. 3
    The members of such a category, taken collectively.
  4. 4
    The distinction and relation between these categories, especially in humans; gender.
  5. 5
    Women; the human female gender and those who belong to it.
  6. 6
    Sexual activity, usually sexual intercourse unless preceded by a modifier.
  7. 7
    Genitalia: a penis or vagina/vulva.

Etymology

Etymology tree Proto-Indo-European *sek-der. Proto-Indo-European *séksusder. Proto-Italic *seksus Latin sexusder. Old French sexeder. Middle English sexe English sex From Middle English sexe (“sex [distinction between male and female] and gender”), from Old French sexe (“genitals; gender”), from Latin sexus (“gender; gender traits; males or females; genitals”), from Proto-Italic *seksus, from Proto-Indo-European *séksus, from *sek- (“to cut, cut off, sever”), thus meaning "section, division" (into male and female). Usage for women influenced by Middle French le sexe (“women”) (attested in 1580). Usage for third and additional sexes calqued from French troisième sexe, referring to masculine women in 1817 and homosexuals in 1847. First used by Lord Byron and others in English in reference to Catholic clergy. Usage for sexual intercourse first attested in 1899 (in the writings of H. G. Wells).

Synonyms

This word in other languages

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 "sex"?
"sex" is spelled S-E-X. The IPA pronunciation is /sɛks/.
What does "sex" mean?
As a noun, "sex" means: A category into which sexually-reproducing organisms are divided on the basis of their reproductive roles in their species; the system of such categories, which can differ by organism or by taxonom...
What words are commonly confused with "sex"?
"sex" is commonly confused with "so", "SI", "SS". These words look or sound similar but have different meanings. PlainSpell provides detailed comparisons for each pair.
How do you pronounce "sex"?
The IPA (International Phonetic Alphabet) transcription for "sex" is /sɛks/. Click the speaker icon on the pronunciation badge above to hear it spoken aloud where audio is available.
What is the origin of the word "sex"?
Etymology tree Proto-Indo-European *sek-der. Proto-Indo-European *séksusder. Proto-Italic *seksus Latin sexusder. Old French sexeder. Middle English sexe English sex From Middle English sexe (“sex [distinction between male and female] and gender”)... See the full etymology section above for more details.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Using “sex”

The practical upshot for anyone who landed here from a spell-check.

  • The one correct English spelling is S-E-X - every other letter order is a misspelling in standard orthography.
  • Say it as /sɛks/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
  • Don't mix it up with “so” - see the side-by-side comparison. sex vs so
  • 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.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list FrequencyWords open word-frequency list