fission
/ˈfɪʃən/
"fission" is a 7-letter English headword indexed on PlainSpell.
The verdict
“fission” is a moderately-common English word, ranked #25,059 in English word frequency and used as a noun.
- #25,059
- frequency rank, English
- 7
- letters
- 9
- tracked misspellings
- 4
- confusable pairs
According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - The process whereby one item splits to become two.
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 | fission |
| Language | English |
| Part of speech | Noun |
| IPA | /ˈfɪʃən/ |
| Letters | 7 |
| Frequency rank | #25,059 |
| Misspellings tracked | 9 |
| Confusable pairs | 4 |
| Source | Wiktionary (kaikki.org) |
Where “fission” sits in English frequency
Spelling & Dictionary Insight
The English entry for fission is 7 letters long, classified as a noun, and transcribed in the International Phonetic Alphabet as /ˈfɪʃən/. Corpus data places it at rank #25,059 in overall English word frequency, marking it as uncommon enough that many writers pause before typing it. Wiktionary records 3 distinct senses for this headword, so context determines which meaning a reader should apply.
Our generated misspelling index lists 9 likely wrong-spelling variants for fission, with forms such as "ffission", "fision", and "fisison". 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 4 confusable-pair relationships, "fusion", "fashion", "fiction", and more, a pairing that trips writers up because the two words share enough sound or shape to blur together.
Etymologically, the entry records: Borrowed from Latin fissiōnem, accusative singular of fissiō (“the act of breaking up”), from findō (“split, divide”). The correct English form is fission, spelled F-I-S-S-I-O-N.
Definition
- 1The process whereby one item splits to become two.
- 2nuclear fission: The process of splitting the nucleus of an atom into smaller particles.
- 3The process by which a bacterium splits to form two daughter cells.
Etymology
Borrowed from Latin fissiōnem, accusative singular of fissiō (“the act of breaking up”), from findō (“split, divide”).
This word in other languages
Common misspellings
Also misspelled as: ffission,fision,fisison,fissino,fissionn,fissoin,fistion,fsision,ifssion
Misspelling Pattern Breakdown
How far each generated variant is from the correct spelling of fission - 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
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Using “fission”
The practical upshot for anyone who landed here from a spell-check.
- The one correct English spelling is F-I-S-S-I-O-N - every other letter order is a misspelling in standard orthography.
- Say it as /ˈfɪʃən/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
- Don't mix it up with “fusion” - see the side-by-side comparison. fission vs fusion
- 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.