actinium
noun/ækˈtɪniəm/
Etymology Borrowed from French actinium. actin- + -ium.
1
Usually A radioactive, metallic chemical element (symbol: Ac) with an atomic number of 89; found in uranium ores.
- Derived terms
- actinate, actinide, actiniferous, actinium A, actinium B, actinium C, actinium emanation, actinium fluoride, actinium-K, actinium series, eka-actinium, protactinium, radioactinium