Source : WordNet®

meltdown
     n 1: severe overheating of the core of a nuclear reactor
          resulting in the core melting and radiation escaping
          [syn: {nuclear meltdown}]
     2: a disaster comparable to a nuclear meltdown; "there is
        little likelihood of a meltdown comparable to the American
        banking collapse in March 1933"

Source : Free On-Line Dictionary of Computing

meltdown
     
        {network meltdown}