n :  a heavy radioactive gaseous element of the group of inert gases formed by disintegration of radium and used similarly to radium in medicine - symbol Rn - called also radium emanation  - see ELEMENTtable   .
 
 
 
Similar sounding terms:  ra·di·an  re·tain  ret·i·na  Ret·in-A 
 
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