/ray"don/ , n. Chem.
a chemically inert, radioactive gaseous element produced by the decay of radium: emissions produced by outgassing of rock, brick, etc. are a health hazard. Symbol: Rn; at. no.: 86; at. wt.: 222.
[ 1915-20; RAD(IUM) + -ON 2 ]
/ray"don/ , n. Chem.
a chemically inert, radioactive gaseous element produced by the decay of radium: emissions produced by outgassing of rock, brick, etc. are a health hazard. Symbol: Rn; at. no.: 86; at. wt.: 222.
[ 1915-20; RAD(IUM) + -ON 2 ]
Random House Webster's Unabridged English dictionary. Полный английский словарь Вебстер - Random House . 2012