adenine [adenines]◼◼◼(base that pairs with thymine or uracil) noun [UK: ˈæ.də.niːn] [US: ˈæ.də.ˌnin]DNA is composed of four nucleotides: adenine, thymine, cytosine and guanine. = L'ADN est composé de quatre nucléotides : adénine, thymine, cytosine et guanine.