Cytosine

//ˈsaɪtəsiːn// noun

noun ·Rare ·Advanced level

Definitions

Noun
  1. 1
    A 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."

  2. 2
    a base found in DNA and RNA and derived from pyrimidine; pairs with guanine wordnet

Synonyms

All synonyms
c

Example

More examples

"DNA is composed of four nucleotides: adenine, thymine, cytosine and guanine."

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.

Related phrases

cytosine arabinosidehydrogen bond

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Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.