: 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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In 2022, advances in DNA technology led investigators with the Santa Clara County Sheriff’s Office to identify the remains of another one of Jesperson’s victims as Patricia Skiple. Clara Harter, Los Angeles Times, 28 Aug. 2026 Authorities with the medical examiner’s office and the police department’s Major Crimes Unit were able to confirm the body belonged to Hall using Rapid DNA terminals at both agencies, according to police. Justin Muszynski, Hartford Courant, 28 Aug. 2026 The Lordstown Police Department helped investigators obtain a DNA sample from the relative, which matched the DNA profile developed from the remains found years earlier at Putt Lake. Darrell Smith, Sacbee.com, 27 Aug. 2026 Blood on the gun matched Williams’ DNA, and blood in Humphreys’ truck matched Brown’s DNA, according to court documents. ABC News, 27 Aug. 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 1 Sep. 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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