A highly unstable radioactive element, the heaviest of the halogen series, that resembles iodine in solution. Its longest lived isotope has a mass number of 210 and has a half-life of 8.3 hours.
"Oooh, I made Asta-*BOOOOOOOOOOOOOM*"
by Tarn June 05, 2005
Top Definition
Element number 85, the heaviest naturally occurring halogen. It is one of the most unstable elements in nature, with its longest half-life at only just over 8 hours, so much so that at any given time less than a gram is believed to exist in the entire Earth, making it also one of the rarest naturally occurring elements. Most notably, it is the only element which requires one to say both "ass" and "tit" in its name.
Chemist: "I've successfully isolated a few thousand atoms of astatine-210 in this chamber!"

Other guy: "lol, asstitine"
by StupidBunny August 13, 2014
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