certain

/ˈsɜː.tən/

//ˈsɜː.tən// adj

"certain" is a 7-letter English headword indexed on PlainSpell.

The verdict

“certain” is in the everyday core of English, ranked #707 in English word frequency and used as an adjective.

#707
frequency rank, English
7
letters
10
tracked misspellings
8
confusable pairs

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - Sure in one's mind, positive; absolutely confident in the truth of something.

Visual similarity to commonly confused words

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

certain vs Curtin
57% similar
certain vs contain
71% similar
certain vs curtain
86% similar

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

Key facts for certain
PropertyValue
Headwordcertain
LanguageEnglish
Part of speechAdjective
IPA/ˈsɜː.tən/
Letters7
Frequency rank#707
Misspellings tracked10
Confusable pairs8
SourceWiktionary (kaikki.org)

Where “certain” 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). certain 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 certain is 7 letters long, classified as an adjective, and transcribed in the International Phonetic Alphabet as /ˈsɜː.tən/. Corpus data places it at rank #707 in overall English word frequency, putting it firmly in the everyday core of the language. Wiktionary records 10 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 certain, with forms such as "ccertain", "ceratin", and "cerrtain". 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 8 confusable-pair relationships, "Curtin", "contain", "curtain", and more, a pairing that trips writers up because the two words share enough sound or shape to blur together.

Etymologically, the entry records: From Middle English certeyn, certein, certain, borrowed from Old French certain, from a Vulgar Latin unattested form *certānus, extended form of Latin certus (“fixed, resolved, certain”), of the same origin as cretus, past participle of cernere (“to separat… The correct English form is certain, spelled C-E-R-T-A-I-N.

Definition

  1. 1
    Sure in one's mind, positive; absolutely confident in the truth of something.
  2. 2
    Not to be doubted or denied; established as a fact.
  3. 3
    Sure to happen, inevitable; assured.
  4. 4
    Unfailing; infallible.
  5. 5
    Fixed; regular; determinate.
  6. 6
    Particular and definite, but unspecified or unnamed; used to introduce someone or something without going into further detail.
  7. 7
    Used to denote that the speaker is referring to a specific person or thing that they do not want to name directly, implying that the listener should infer the identity of the referent.
  8. 8
    Named but not previously mentioned.
  9. 9
    Used before the name of someone famous that people are expected to know.
  10. 10
    Determined; resolved.

Etymology

From Middle English certeyn, certein, certain, borrowed from Old French certain, from a Vulgar Latin unattested form *certānus, extended form of Latin certus (“fixed, resolved, certain”), of the same origin as cretus, past participle of cernere (“to separate, perceive, decide”). Displaced native Middle English wis, iwis (“certain, sure”) (from Old English ġewiss (“certain, sure”)) and alternative Middle English spelling sertane (“some, certain”).

Synonyms

Antonyms

This word in other languages

Common misspellings

Also misspelled as: ccertain,ceratin,cerrtain,certainn,certani,certian,certtain,cetrain,cretain,ecrtain

Misspelling Pattern Breakdown

How far each generated variant is from the correct spelling of certain - expressed in single-character edits (insert, delete, or swap one letter). Bigger bars stand out at a glance; a one-edit slip is the hardest to catch.

ccertain1ceratin2cerrtain1certainn1certani2certian2certtain1cetrain2
Edit distance from "certain"

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 "certain"?
"certain" is spelled C-E-R-T-A-I-N. The IPA pronunciation is /ˈsɜː.tən/.
What does "certain" mean?
As an adjective, "certain" means: Sure in one's mind, positive; absolutely confident in the truth of something.
What words are commonly confused with "certain"?
"certain" is commonly confused with "Curtin", "contain", "curtain". These words look or sound similar but have different meanings. PlainSpell provides detailed comparisons for each pair.
How do you pronounce "certain"?
The IPA (International Phonetic Alphabet) transcription for "certain" is /ˈsɜː.tən/. 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 "certain"?
From Middle English certeyn, certein, certain, borrowed from Old French certain, from a Vulgar Latin unattested form *certānus, extended form of Latin certus (“fixed, resolved, certain”), of the same origin as cretus, past participle of cernere (“... 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 “certain”

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

  • The one correct English spelling is C-E-R-T-A-I-N - every other letter order is a misspelling in standard orthography.
  • Say it as /ˈsɜː.tən/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
  • Don't mix it up with “Curtin” - see the side-by-side comparison. certain vs Curtin
  • 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