: any of various nucleic acids that are usually the molecular basis of heredity, are constructed of a double helix held together by hydrogen bonds between purine and pyrimidine bases (see base entry 1 sense 6b) which project inward from two chains containing alternate links of deoxyribose and phosphate, and that in eukaryotes are localized chiefly in cell nuclei compare recombinant dna

Illustration of DNA

Illustration of dna
  • A molecular model
  • 1 hydrogen
  • 2 oxygen
  • 3 carbon in the helical phosphate ester chains
  • 4 carbon and nitrogen in the cross-linked purine and pyrimidine bases
  • 5 phosphorus
  • B double helix

Examples of DNA in a Sentence

Recent Examples on the Web
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Defense attorney Michael Burt, meanwhile, tried to discredit the DNA and ballistics reports, questioning forensic witnesses about semantics in lab policies and the quality of the evidence collected. Nicki Brown, CNN Money, 11 July 2026 Both experts acknowledged that the tests are not infallible, can’t determine exactly when DNA was left on an item, and can't confirm the source of DNA with absolute certainty. N'dea Yancey-Bragg, USA Today, 10 July 2026 Penned in partnership with Vallicelli Design studio, the newcomer is blessed with Pershing’s sporty DNA, combining a clean, contemporary silhouette with impressive performance specs. Rachel Cormack, Robb Report, 10 July 2026 Current coach Mohammed Ouahbi embodies this national DNA, giving Morocco a tactical edge to challenge France. Chris Evans, Forbes.com, 9 July 2026 See All Example Sentences for DNA

Word History

Etymology

deoxyribonucleic acid

First Known Use

1944, in the meaning defined above

Time Traveler
The first known use of DNA was in 1944

Browse Nearby Words

Cite this Entry

“DNA.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/DNA. Accessed 15 Jul. 2026.

Kids Definition

: any of various nucleic acids that are located especially in cell nuclei, are usually the chemical basis of heredity, and are composed of two nucleotide chains held together by hydrogen bonds in a pattern resembling a flexible twisted ladder compare rna

Medical Definition

: any of various nucleic acids that are usually the molecular basis of heredity, are constructed of a double helix held together by hydrogen bonds between purine and pyrimidine bases which project inward from two chains containing alternate links of deoxyribose and phosphate, and that in eukaryotes are localized chiefly in cell nuclei

called also deoxyribonucleic acid

see recombinant dna

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