[ gwah-neen ]
/ ˈgwɑ nin /

noun Biochemistry.

a purine base, C5H5N5O, that is a fundamental constituent of DNA and RNA, in which it forms base pairs with cytosine. Symbol: G

Nearby words

  1. guangxi zhuang,
  2. guangxi zhuang autonomous region,
  3. guangzhou,
  4. guangzhouwan,
  5. guanidine,
  6. guanine deaminase,
  7. guanine deoxyribonucleotide,
  8. guanine ribonucleotide,
  9. guano,
  10. guanosine

Compare guanosine.

Origin of guanine Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for guanine

British Dictionary definitions for guanine


/ (ˈɡwɑːniːn, ˈɡuːəˌniːn) /


a white almost insoluble compound: one of the purine bases in nucleic acids. Formula: C 5 H 5 N 5 O

Word Origin for guanine

C19: from guano + -ine ²

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 guanine



1850, from guano, from which the chemical first was isolated, + chemical suffix -ine (2).

Online Etymology Dictionary, © 2010 Douglas Harper

Medicine definitions for guanine


[ gwänēn′ ]


A purine base that is an essential constituent of both RNA and DNA.

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

Science definitions for guanine


[ gwänēn′ ]

A purine base that is a component of DNA and RNA, forming a base pair with cytosine. It also occurs in guano, fish scales, sugar beets, and other natural materials. Chemical formula: C5H5ON5.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.