Examples from the Web for actinium
For if actinium was an independent element we would be sure to find actinium haloes.The Birth-Time of the World and Other Scientific Essays|J. (John) Joly
Actinium, an element or elementary substance obtained in minute quantities in connection with the study of radioactivity.
These are generally known as radium emanation, thorium emanation, and actinium emanation.
In this class are now placed also the three radio-active gases, emanating respectively from radium, thorium, and actinium.
Emanium was the name originally proposed by Giesel for the body now known as actinium.
British Dictionary definitions for actinium
Word Origin for actinium
Word Origin and History for actinium
radioactive element discovered in 1899, from Greek actin-, comb. form of aktis (genitive aktinos) "ray, radiance" (see actino-) + chemical suffix -ium.