[ noo-klee-uh-tahyd, nyoo- ]
/ ˈnu kli əˌtaɪd, ˈnyu- /

noun Biochemistry.

any of a group of molecules that, when linked together, form the building blocks of DNA or RNA: composed of a phosphate group, the bases adenine, cytosine, guanine, and thymine, and a pentose sugar, in RNA the thymine base being replaced by uracil.

Nearby words

  1. nucleoside,
  2. nucleoside analogue,
  3. nucleosome,
  4. nucleosynthesis,
  5. nucleotidase,
  6. nucleotides,
  7. nucleotidyltransferase,
  8. nucleotoxin,
  9. nucleus,
  10. nucleus fastigii

Origin of nucleotide

First recorded in 1905–10; alteration of nucleoside

Related formsin·ter·nu·cle·o·tide, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for nucleotides


/ (ˈnjuːklɪəˌtaɪd) /


biochem a compound consisting of a nucleoside linked to phosphoric acid. Nucleic acids are made up of long chains (polynucleotides) of such compounds

Word Origin for nucleotide

C20: from nucleo- + t (added for ease of pronunciation) + -ide

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for nucleotides



1908, from German nucleotid (1908), from nucleo-, modern comb. form of Latin nucleus (see nucleus) + -ide, with -t- for the sake of euphony.

Online Etymology Dictionary, © 2010 Douglas Harper

Medicine definitions for nucleotides


[ nōōklē-ə-tīd′ ]


Any of various compounds consisting of a nucleoside combined with a phosphate group and forming the basic constituent of DNA and RNA.

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Science definitions for nucleotides


[ nōōklē-ə-tīd′ ]

Any of a group of organic compounds composed of a nucleoside linked to a phosphate group. Nucleotides are the basic building blocks of nucleic acids.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Culture definitions for nucleotides


[ (nooh-klee-uh-teyedz) ]

The molecules that form the basic modular structure of the double helix of the DNA molecule. A nucleotide consists of three molecules — a sugar, a phosphate group, and a molecule called a base. If the double helix is a twisted ladder, the sugar and phosphates form the sides of the ladder and pairs of bases form the rungs. There are four different bases, usually abbreviated A, C, G, and T for adenine, cytosine, guanine, and thymine). The order of bases in DNA determines the genetic code.

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.