intron

noun

in·​tron ˈin-ˌträn How to pronounce intron (audio)
: a polynucleotide sequence in a nucleic acid that does not code information for protein synthesis and is removed before translation of messenger RNA compare exon

Examples of intron in a Sentence

Recent Examples on the Web
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Moreover, the mystery around the origins of introns only deepens in light of the extreme variation in where introns tend to show up throughout the eukaryote tree of life. Jake Buehler, Quanta Magazine, 30 Mar. 2023 There are now about a dozen individual changes in the amino acids used to make the protein, and the nearby DNA has picked up both an insertion (an intron) and several deletions. John Timmer, Ars Technica, 23 Feb. 2018 Named for parts of genes called introns and exons, Intrexon was founded in 1998 by Thomas D. Reed and his wife, Jackie, to supply DNA constructs for research with genetically engineered mice. Andrew Pollack, New York Times, 5 Mar. 2016

Word History

Etymology

intervening sequence + -on entry 2

First Known Use

1978, in the meaning defined above

Time Traveler
The first known use of intron was in 1978

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Cite this Entry

“Intron.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/intron. Accessed 8 Sep. 2025.

Medical Definition

intron

noun
in·​tron ˈin-ˌträn How to pronounce intron (audio)
: a polynucleotide sequence in a nucleic acid that does not code information for protein synthesis and is removed before translation of messenger RNA compare exon
intronic adjective

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