guanine

noun

gua·​nine ˈgwä-ˌnēn 

: a purine base C₅H₅N₅O that codes genetic information in the polynucleotide chain of DNA or RNA compare adenine, cytosine, thymine, uracil

Examples of guanine in a Sentence

Recent Examples on the Web

Those rungs are made up of pairs of four different chemical building blocks, called bases — adenine, thymine, cytosine and guanine (A,T,C and G). —F.d. Flam, Mercury News, 26 Nov. 2025

This four-tone greeting is not a specific communication per-se, but the nucleotides of guanine, uracil, adenine, and cytosine, which represent the building blocks of RNA. —Jeff Spry, Space.com, 14 Nov. 2025

Adenine always pairs with thymine, and guanine always pairs with cytosine. —IEEE Spectrum, 2 Oct. 2025

Blue sharks’ changing skin color is enabled by a combination of guanine crystals and melanosomes. —Rafil Kroll-Zaidi, Harpers Magazine, 19 Sep. 2025

Word History

Etymology

guano + -ine; from its being found especially in guano

First Known Use

1850, in the meaning defined above

Rhymes for guanine

• agin
• alkene
• allene
• ameen
• amin
• amine
• arene
• athene
• baleen
• beeline
• benzene
• between

Kids Definition

guanine

noun

gua·​nine ˈgwän-ˌēn 

: a purine base that codes genetic information in DNA and RNA compare adenine, cytosine, thymine, uracil

Medical Definition

guanine

noun

gua·​nine ˈgwän-ˌēn 

: a purine base C₅H₅N₅O that codes genetic information in the polynucleotide chain of DNA or RNA compare adenine, cytosine, thymine, uracil