actinium
n. கதிரியக்கமுடைய உலோகப் பொருள்களில்ஒன்று, அணு எண் க்ஷ்ஹீ கொண்ட தனிப்பொருள்,
Ac*tin"i*um, n. Etym: [Gr. (Chem.) Defn: A supposed metal, said by Phipson to be contained in commercial zinc; -- so called because certain of its compounds are darkened by exposure to light.