actinium
nounmasculinetécnico/ɐkˈtinju/rare
ac·ti·nio
Definition
Radioactive chemical element (symbol Ac, atomic number 89) of the actinide series.
Actinium is a radioactive metal little studied due to its instability.
Actinium was discovered in the early 20th century.
Common collocations
element actiniumradioactivity of actinium
Etymology
Do grego 'aktís' (raio) + elemento químico.