A heterocyclic base, 5-methylpyrimidine-2,4(1H,3H)-dione; it pairs with adenine in DNA.
From thymus + -ine. Thymine was first isolated in 1893 by Albrecht Kossel and Albert Neumann from calves' thymus glands, hence its name.
Practice speaking and memorizing "thymine" and many other words and sentences in English.