diatomic /daɪəˈtɒmɪk/adjective 2noun 1forms 1 adjective2 •Consisting of two atoms. •(rare) Of or relating to diatoms.Cytological studies of the silicon diatomic cell wall, exhibiting the most beautiful diatoms appearance, are presented by Karsten and Holzinger, by Witkowski, and by others. — 2019 noun1 •A diatomic molecule or other species. formsdiatomics