thymine

noun

thy·​mine ˈthī-ˌmēn 

: a pyrimidine base C₅H₆N₂O₂ that is one of the four bases coding genetic information in the polynucleotide chain of DNA compare adenine, cytosine, guanine, uracil

Examples of thymine in a Sentence

Recent Examples on the Web

Scientists have discovered that a sample of the Ryugu asteroid collected by Japan's Hayabusa 2 spacecraft contains the nucleobases adenine, guanine, cytosine, thymine and uracil, the building blocks of DNA and RNA upon which all life is based. —Robert Lea, Space.com, 17 Mar. 2026

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

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

Biology’s four bases—adenine (A), thymine (T), cytosine (C) and guanine (G)—encode the instructions that keep life alive. —Andrew Whalen, Forbes.com, 9 July 2025

Word History

Etymology

International Scientific Vocabulary, from New Latin thymus

First Known Use

1894, in the meaning defined above

Rhymes for thymine

• caiman
• hymen
• liman

Kids Definition

thymine

noun

thy·​mine ˈthī-ˌmēn 

: a pyrimidine base that is one of the bases coding hereditary information in DNA compare adenine, cytosine, guanine, uracil

Medical Definition

thymine

noun

thy·​mine ˈthī-ˌmēn 

: a pyrimidine base C₅H₆N₂O₂ that is one of the four bases coding genetic information in the polynucleotide chain of DNA compare adenine, cytosine, guanine, uracil