Thallous
Pronunciation : Thal"lous
Part of Speech : a.
Definition : Defn: Of or pertaining to thallium; derived from, or containing, thallium; specifically, designating those compounds in which the element has a lower valence as contrasted with the thallic compounds. [Written also thallious.]
(Chem.)
Source : Webster's Unabridged Dictionary, 1913