codon

American  

[koh-don] / ˈkoʊ dɒn /

noun

Genetics.

1. a triplet of adjacent nucleotides in the messenger RNA chain that codes for a specific amino acid in the synthesis of a protein molecule.

---

codon British  

/ ˈkəʊdɒn /

noun

1. genetics biochem a unit that consists of three adjacent bases on a DNA molecule and that determines the position of a specific amino acid in a protein molecule during protein synthesis

---

codon Scientific  

/ kō′dŏn′ /

1. A sequence of three adjacent nucleotides on a strand of a nucleic acid (such as DNA) that constitutes the genetic code for a specific amino acid that is to be added to a polypeptide chain during protein synthesis. Some amino acids are coded for by more than one codon, and some codons do not signal a particular amino acid but rather signal a stop to protein synthesis.

---

codon Cultural  

1. A group of three bases on the DNA molecule. Each codon determines the identity of one amino acid in proteins made by the cell.

---

Etymology

Origin of codon

An Americanism dating back to 1960–65; code + -on ¹

Compare meaning

How does codon compare to similar and commonly confused words? Explore the most common comparisons:

• codon vs. anticodon

Example Sentences

These findings change how scientists think about gene regulation, showing that codon choice itself plays a direct role in controlling gene expression in human cells.

From Science Daily • Apr. 9, 2026

Even so, each codon has traditionally been understood to carry only one meaning.

From Science Daily • Feb. 28, 2026

When pyrrolysine is scarce, the same codon functions as a stop signal.

From Science Daily • Feb. 28, 2026

The initiator tRNA interacts with the AUG start codon, and links to a special form of the amino acid methionine that is typically removed from the polypeptide after translation is complete.

From Textbooks • Apr. 25, 2013

Each amino acid is defined by a three- nucleotide sequence called the triplet codon.

From Textbooks • Apr. 25, 2013