| Monatomic 1. (adv.) Consisting of, or containing, one atom; as, the molecule of mercury is monatomic. 2. (adv.) Having the equivalence or replacing power of an atom of hydrogen; univalent; as, the methyl radical is monatomic. Thesaurus Entries a certain, an, any, any one, atomatic, atomiferous, atomistic, corpuscular, cyclic, diatomic, dibasic, either, embryonic, evanescent, exclusive, germinal, granular, heteroatomic, heterocyclic, hexatomic, homocyclic, impalpable, imperceptible, imponderable, inappreciable, indiscernible, individual, indivisible, infinitesimal, intangible, integral, invisible, irreducible, isobaric, isocyclic, isoteric, isotopic, lone, microcosmic, microscopic, molecular, monadic, monatomic, monistic, one, pentatomic, simple, single, singular, sole, solid, solitary, subatomic, tenuous, tetratomic, thin, triatomic, tribasic, ultramicroscopic, unanalyzable, undivided, uniform, unique, unitary, unseeable, whole |