monatomic molecule

Chem.: A molecule containing one atom. mo-nâul', s. [Native name.] Ornith.: [IMPEYAN-PHEASANT.] mon-ax-on-i-dæ, s. pl. [Pref. mon-: Gr. axōn (gen it. axonos )=an axis, and Lat. fem. pl. adj. suff. -idœ.] Zool.: A sub-order of Silicispongie, distinguished by the presence of uni-axial, and the absence of tetractinellid and hexactinellid spicules. Schmidt divides the sub-order into five families: Renierinæ, Des mac i dine, Suber it i dine, Chal in ops i dinæ, and Chalinese.