codon

noun

co·​don ˈkō-ˌdän How to pronounce codon (audio)
: a specific sequence of three consecutive nucleotides that is part of the genetic code and that specifies a particular amino acid in a protein or starts or stops protein synthesis

called also triplet

Examples of codon in a Sentence

Recent Examples on the Web
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Next, three sets of those letters (called codons) work together to form one of 20 amino acids. Paul Smaglik, Discover Magazine, 23 Jan. 2025 Every three consecutive nucleotides in this chain can constitute what’s called a codon. Bruce Y. Lee, Forbes, 5 Jan. 2022 The amino acid glycine is encoded by four different codons (GGU, GGC, GGA, and GGG), the amino acid leucine is encoded by six different codons, and so forth. IEEE Spectrum, 14 Oct. 2021 One way is using genetic data to look at codons—triplets of DNA or RNA letters that are the instructions for making proteins. Megan Molteni, Wired, 23 Jan. 2020 One way that viruses adapt is by encoding proteins using the same choice of codons as their host. David Cyranoski, Scientific American, 23 Jan. 2020

Word History

First Known Use

1962, in the meaning defined above

Time Traveler
The first known use of codon was in 1962

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Cite this Entry

“Codon.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/codon. Accessed 9 Sep. 2025.

Medical Definition

codon

noun
co·​don ˈkō-ˌdän How to pronounce codon (audio)
: a specific sequence of three consecutive nucleotides that is part of the genetic code and that specifies a particular amino acid in a protein or starts or stops protein synthesis

called also triplet

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