What does astatine mean?

astatine meaning in Etymology Dictionary

radioactive element, named 1947, from Greek astatos "unstable" (see astatic) + chemical suffix -ine (2). So called for the brief half-life and not enough stable isotopes. "The factor seems not to have a well balanced kind and most likely doesn't occur in general" [Flood, "Origin of Chemical Names"].

astatine meaning in General Dictionary

an extremely volatile radioactive factor (the heaviest associated with halogen show); a decay item of uranium and thorium