a gaseous radioisotope of radon, formed by disintegration of actinium: at. no. 86; half-life of 3.92 seconds
Origin of actinonModern Latin ; from actinium + -on
A radioactive isotope of radon, Rn-219, having a half-life of 3.96 seconds and produced by the disintegration of actinium.
Origin of actinonactin(ium) + –on2.