carbon dioxide
/ˌkɑː.bən daɪˈɒk.saɪd/
"carbon-dioxide" is a 13-letter English headword indexed on PlainSpell.
The verdict
“carbon dioxide” is uncommon English (outside the top frequency list), classed as a noun. The kind of spelling people second-guess.
- Unranked
- below top-frequency English
- 14
- letters
According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - The normal oxide of carbon, CO₂; a colorless, odorless gas formed during respiration and combustion and consumed by plants during photosynthesis.
Corpus desk
Index EN-carbon-dioxide · carbon dioxide · English
carbon dioxide · unranked · 0 variants · 0 confusables
- FREQ-UNRANKED Unranked
- LEN-MEGA 14 letters
- VOW-6 6 vowels
- CONFUS-0 No pairs
- VAR-0 0 variants
- BOOK-THIN "C" thin
- PHOTO-UNK Peer pending
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.
| Property | Value |
|---|---|
| Headword | carbon dioxide |
| Language | English |
| Part of speech | Noun |
| IPA | /ˌkɑː.bən daɪˈɒk.saɪd/ |
| Letters | 14 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Where “carbon dioxide” sits in English frequency
Rare enough to double-check
carbon dioxide is uncommon English outside the top frequency list, classed as anoun, transcribed /ˌkɑː.bən daɪˈɒk.saɪd/. Rarity is why readers land here mid-draft. Gloss: "The normal oxide of carbon, CO₂; a colorless, odorless gas formed during respiration and combustion and consumed by plants during photosynthesis.".
Zero misspellings are on record for carbon dioxide in our index, typically a sign the spelling maps closely to how the word sounds. Our confusable-pair dataset has no match for it, which typically means the spelling is too distinctive to be mistaken for another word.
This headword's origin isn't recorded in our source data, so its spelling is best explained by sound-to-letter mapping rather than etymology. The correct English form is carbon dioxide, spelled C-A-R-B-O-N- -D-I-O-X-I-D-E.
Definition
- 1The normal oxide of carbon, CO₂; a colorless, odorless gas formed during respiration and combustion and consumed by plants during photosynthesis.
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). See the methodology for how each field is sourced and updated.
PlainSpell is rendered directly from structured Wiktionary extracts and open word-frequency lists, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of May 6, 2026. Primary sources: Wiktionary (via kaikki.org) and FrequencyWords.
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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.