dictionary.pt
actinium
nounmasculinetechnicalrare/ɐkˈtinju/ac·ti·nio
Definition
1Radioactive chemical element (symbol Ac, atomic number 89) of the actinide series.
Usage examples
“Actinium is a radioactive metal little studied due to its instability.”
“Actinium was discovered in the early 20th century.”
Common combinations
element actiniumradioactivity of actinium