cytosine

C3Y4T1O1S1I1N1E1
/ˈsaɪtəsiːn/

noun

A heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA (by means of three hydrogen bonds).

Similar
C
OriginGerman Cytosin ← Ancient Greek κύτος →
UncommonScrabble 13
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Meanings

nouncytosine (plural cytosines)

plural cytosines

  1. biochemistryA heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA (by means of three hydrogen bonds).

    Then he found them, the substances that made up the four-letter alphabet in whose language all life is written — adenine and cytosine, guanine and thymine.

    1997, Ian McEwan, Enduring Love, Vintage (1998), page 164

Synonyms & antonyms

nouna base found in DNA and RNA and derived from pyrimidine; pairs with guanine

Similar
C
Broader
pyrimidine
Also see
c

Synonym sets from Open English WordNet, CC BY 4.0.

Origin

  1. Ancient Greekκύτος
  2. GermanCytosin
  3. Englishcytosine

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.

More words from German, Ancient Greek

Full word history & related roots →

Translations

Catalan citosina
  • citosinaheterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
Chinese Mandarin 胞嘧啶
  • 胞嘧啶 (bāomìdìng)heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
Czech cytosin
  • cytosinheterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
Esperanto citozino
  • citozinoheterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
Finnish sytosiini
  • sytosiiniheterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
French cytosine
  • cytosineheterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
German Cytosin
  • Cytosinheterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
Hungarian citozin
  • citozinheterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
Icelandic sýtósín, sýtosín
  • sýtósínheterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
  • sýtosínheterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
Irish cíotóisín
  • cíotóisínheterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
Italian citosina
  • citosinaheterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
Japanese シトシン
  • シトシン (shitoshin)heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
Polish cytozyna
  • cytozynaheterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
Portuguese citosina
  • citosinaheterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
Russian цитози́н
  • цитози́н (citozín)heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
Spanish citosina
  • citosinaheterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
Turkish sitozin
  • sitozinheterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
Ukrainian цитозин
  • цитозин (cytozyn)heterocyclic base, 4-aminopyrimidin-2(1H)-one, which pairs with guanine in DNA and RNA
Cite this entry
APA

cytosine. (n.d.). In WatkinsX Dictionary. Retrieved November 2, 2026, from https://dictionary.watkinsx.com/word/cytosine

MLA

“cytosine.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/cytosine. Accessed November 2, 2026.

Chicago

WatkinsX Dictionary, s.v. “cytosine,” accessed November 2, 2026, https://dictionary.watkinsx.com/word/cytosine.

Source: cytosine on Wiktionary, CC BY-SA 4.0.