cytosine
/ˈsaɪtəsiːn/
"cytosine" is a 8-letter English headword indexed on PlainSpell.
The verdict
“cytosine” is uncommon English (frequency #73,101 among 43,570 “C” headwords), classed as a noun. The kind of spelling people second-guess.
- #73,101
- frequency rank, English
- 43,570
- “C” headwords
According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - A heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA (by means of three hydrogen bonds).
| Property | Value |
|---|---|
| Headword | cytosine |
| Language | English |
| Part of speech | Noun |
| IPA | /ˈsaɪtəsiːn/ |
| Letters | 8 |
| Frequency rank | #73,101 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Where “cytosine” sits in English frequency
Rare enough to double-check
cytosine is uncommon English at frequency #73,101 among 43,570 “C” headwords, classed as anoun, transcribed /ˈsaɪtəsiːn/. Rarity is why readers land here mid-draft. Gloss: "A heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA (by means of three hydrogen bonds).".
We couldn't generate a plausible misspelling set for cytosine, suggesting the orthography follows predictable English patterns. This headword has no recorded confusable partner, which usually means its spelling is distinct enough that readers don't reach for a similar-looking word instead.
Etymologically, the entry records: After German Cytosin, equivalent to Ancient Greek κύτος (kútos) + -ine. Cytosine was discovered and named by the German biochemists Albrecht Kossel and Albert Neumann in 1894 when it was hydrolyzed from calf thymus tissues. The correct English form is cytosine, spelled C-Y-T-O-S-I-N-E.
Definition
- 1A heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA (by means of three hydrogen bonds).
Etymology
After German Cytosin, equivalent to Ancient Greek κύτος (kútos) + -ine. Cytosine was discovered and named by the German biochemists Albrecht Kossel and Albert Neumann in 1894 when it was hydrolyzed from calf thymus tissues.
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); 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 “cytosine”
The practical upshot for anyone who landed here from a spell-check.
- The one correct English spelling is C-Y-T-O-S-I-N-E - every other letter order is a misspelling in standard orthography.
- Say it as /ˈsaɪtəsiːn/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
- Browse more English words and confusable pairs in the same reference. English words
Other uncommon English words near this rank
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.