CO2

[ˌt͡seːoˈt͡svaɪ̯]

/[ˌt͡seːoˈt͡svaɪ̯]/ noun

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

The verdict

“CO2” sits in 20 confusable pairs (corpus #4,186) as a noun. The look-alike neighbours are the real trap.

#4,186
frequency rank, German
1,273
“C” headwords
20
confusable pairs

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - chemische Summenformel von Kohlendioxid

Corpus desk

Index DE-co2 · CO2 · German

CO2 · rank #4,186 · 0 variants · 20 confusables

  • FREQ-COMMON #4,186
  • LEN-MID 3 letters
  • VOW-1 1 vowel
  • CONFUS-HIGH 20 pairs
  • VAR-0 0 variants
  • BOOK-MID 1,273
  • PHOTO-FINISH brauchte

Nearest frequency peer: brauchte (-1 rank slots)

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.

Frequency neighbourhood for “CO2”

Lower corpus rank = more everyday usage (inverted bar length for readability)

corpus weight

What this shows Bars show where “CO2” sits against the nearest ranked German headwords in the FrequencyWords band, not a reprint of letter-browse containment.

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).

CO2 vs CT
33% similar
CO2 vs Cs
33% similar
CO2 vs Cr
33% similar

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

Key facts for CO2
PropertyValue
HeadwordCO2
LanguageGerman
Part of speechNoun
IPA[ˌt͡seːoˈt͡svaɪ̯]
Letters3
Frequency rank#4,186
Misspellings tracked0
Confusable pairs20
SourceWiktionary (kaikki.org)

Where “CO2” sits in German 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).CO2 lands here:

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

Ticks step logarithmically, so each one marks a roughly tenfold drop in how often the word turns up. Source: FrequencyWords open word-frequency list.

Easy to mix with look-alikes

The spelling risk for CO2 is neighbouring look-alikes ("CT", "Cs", …), not just typos; it is anoun pronounced [ˌt͡seːoˈt͡svaɪ̯]. Frequency #4,186 among 1,273 “C” headwords. Gloss: "chemische Summenformel von Kohlendioxid".

Our edit-distance generator produced no likely misspellings for CO2, typically a sign the spelling maps closely to how the word sounds. It also participates in 20 confusable-pair relationships, "CT", "Cs", "Cr", and more, since the words sound or look close enough that writers reach for the wrong one mid-sentence.

Our source data has no etymology on file for this entry, leaving phoneme-to-grapheme mapping as the best guide to its spelling rather than a borrowing history. The correct German form is CO2, spelled C-O-2.

Definition

  1. 1
    chemische Summenformel von Kohlendioxid

Recorded use

Wiktionary examples

These source excerpts show how CO2 appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.

  1. Der Ausstoß großer Mengen an CO2 in die Atmosphäre führt zur Klimaerwärmung.
  2. „Es wird behauptet, der Klimaeffekt eines Chlor-Fluor-Kohlenwasserstoff-Moleküls sei 10 000mal größer als der von CO2.“

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 German corpus, MIT). 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 September 3, 2026. Primary sources: Wiktionary (via kaikki.org) and FrequencyWords.

Frequently Asked Questions

How do you spell "CO2"?
"CO2" is spelled C-O-2. The IPA pronunciation is [ˌt͡seːoˈt͡svaɪ̯].
What does "CO2" mean?
As a noun, "CO2" means: chemische Summenformel von Kohlendioxid
What words are commonly confused with "CO2"?
"CO2" is commonly confused with "CT", "Cs", "Cr". These words look or sound similar but have different meanings. PlainSpell provides detailed comparisons for each pair.
How do you pronounce "CO2"?
The IPA (International Phonetic Alphabet) transcription for "CO2" is [ˌt͡seːoˈt͡svaɪ̯]. Click the speaker icon on the pronunciation badge above to hear it spoken aloud where audio is available.
What language does "CO2" come from?
"CO2" is a German word. PlainSpell's reference spans five languages -- English, Spanish, Portuguese, French, and German -- with definitions, pronunciations, and spelling data for each.
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 German words by spelling shape

Same letter count and similar misspelling depth for "CO2", not the corpus desk frequency band.

Same letter count

Frequency-ranked German headwords with 3 letters (nearest by frequency rank).

Wut#4,174Leo#4,217Rio#4,154off#4,224

What to do next

You've looked up "CO2". Here's where to go from here.

  • "CO2" maps to 20 confusable pairs in this vintage; the highest-scored is "CT". View pair
  • Usage frequency rank #4,186 among German headwords in this corpus. Corpus statistics
  • Browse more German words in the "C" letter cohort. C–Z browse

PlainSpell is a reference corpus, not spelling advice. Verify unusual forms in context.

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