assertion

/əˈsɜːʃən/

//əˈsɜːʃən// noun

By · According to Wiktionary data (CC BY-SA) ·

"assertion" is a 9-letter English headword indexed on PlainSpell.

The verdict

“assertion” has 12 generated spelling variants in the English index at frequency #12,366. The variants make it a useful spelling check.

#12,366
frequency rank, English
3,931
“A” headwords
12
tracked misspellings
2
confusable pairs

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - The act of asserting; positive declaration or averment.

Corpus desk

Index EN-assertion · assertion · English

assertion · rank #12,366 · 12 variants · 2 confusables

  • FREQ-MID #12,366
  • LEN-LONG 9 letters
  • VOW-4 4 vowels
  • CONFUS-LOW 2 pairs
  • VAR-MID 12 variants
  • BOOK-MID 3,931
  • PHOTO-FINISH Assad

Nearest frequency peer: Assad (-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 “assertion”

Same rarity band: useful when a typo lands on a peer headword

corpus weight

What this shows “assertion” sits among these FrequencyWords peers; misspelling depth is tracked separately in the edit-distance chart.

Source FrequencyWords open word-frequency list As of September 3, 2026

Visual similarity to commonly confused words

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

assertion vs assertive
78% similar
assertion vs asserting
78% similar

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

Key facts for assertion
PropertyValue
Headwordassertion
LanguageEnglish
Part of speechNoun
IPA/əˈsɜːʃən/
Letters9
Frequency rank#12,366
Misspellings tracked12
Confusable pairs2
SourceWiktionary (kaikki.org)

Frequency seat of misspelling magnet “assertion”

This scale runs from the tiny cluster of words that carry ordinary speech (left) to the long tail of words almost nobody reaches for (right).assertionlands here:

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

Scale is logarithmic (each tick is 10× rarer). Same rarity band neighbours include “Assad” (#12,365), “astronomy” (#12,367), “atop” (#12,368). Among 3,931 “A” headwords, “assertion” is #12,366. Source: FrequencyWords open word-frequency list.

A misspelling magnet

The generator records 12 spelling variants around assertion (IPA /əˈsɜːʃən/), anoun. Corpus frequency is #12,366 among 3,931 “A” headwords. Wiktionary lists 6 senses, so context still picks the gloss.

Our generated misspelling index lists 12 likely wrong-spelling variants for assertion, with forms such as "asertion", "asesrtion", and "asseriton". 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. It also participates in 2 confusable-pair relationships, "assertive", "asserting", 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 assercioun, from Latin assertiō. By surface analysis, assert + -ion. The correct English form is assertion, spelled A-S-S-E-R-T-I-O-N.

Definition

  1. 1
    The act of asserting; positive declaration or averment.
  2. 2
    Something which is asserted; a declaration; a statement asserted.
  3. 3
    A statement or declaration which lacks support or evidence.
  4. 4
    Maintenance; vindication.
  5. 5
    A statement in a program asserting a condition expected to be true at a particular point, used in debugging.
  6. 6
    The set of information that the statement preparer is providing in a financial statement audit.

Recorded use

Wiktionary examples

These source excerpts show how assertion appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.

  1. You're a man of strong assertions!
  2. Suppose you are given the semifactual assertion, "even if Nora had liked mathematics then she would have became^([sic]) a scientist" and then you find out that Nora did in fact become a scientist.

Etymology

From Middle English assercioun, from Latin assertiō. By surface analysis, assert + -ion.

Synonyms

accusationallegationcensurechargecriminationimpeachment

This word in other languages

afirmación(Español)assertion(Français)Versicherung(Deutsch)asserção(Português)

Common misspellings

Also misspelled as:

  • asertion
  • asesrtion
  • asseriton
  • asserrtion
  • assersion
  • assertino
  • assertionn
  • assertoin
  • asserttion
  • assetrion
  • assretion
  • sasertion

Misspelling Pattern Breakdown

How far each generated variant is from the correct spelling of assertion - measured in single-character edits (insert, delete, or substitute a letter). Larger bars are easier to catch; one-edit slips are the sneakiest.

asertion1asesrtion2asseriton2asserrtion1assersion1assertino2assertionn1assertoin2
Edit distance from "assertion"

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 "assertion"?
"assertion" is spelled A-S-S-E-R-T-I-O-N. The IPA pronunciation is /əˈsɜːʃən/.
What does "assertion" mean?
As a noun, "assertion" means: The act of asserting; positive declaration or averment.
What words are commonly confused with "assertion"?
"assertion" is commonly confused with "assertive", "asserting". These words look or sound similar but have different meanings. PlainSpell provides detailed comparisons for each pair.
How do you pronounce "assertion"?
The IPA (International Phonetic Alphabet) transcription for "assertion" is /əˈsɜːʃən/. 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 "assertion"?
From Middle English assercioun, from Latin assertiō. By surface analysis, assert + -ion. 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.

Similar English words by spelling shape

Same letter count and similar misspelling depth for "assertion", not the corpus desk frequency band.

Same letter count

Frequency-ranked English headwords with 9 letters (nearest by frequency rank).

astronomy#12,367allergies#12,360accessory#12,354bothering#12,378

Similar misspelling depth

Headwords with a similar count of attested misspellings (12 here; floor ≥5).

coherent12 variantscomrades12 variantsconceded12 variantssymptom12 variants

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

Source: FrequencyWords open word-frequency list