- noun a point in an accident in a nuclear reactor at which the fuel overheats and the core melts while the nuclear reaction is still in progress
- A complete halt of a computer system or network. May be caused, for instance, by a program deficiency, a hardware failure, or network congestion.
- The complete halt of a communications network. The term usually entails a condition of excess traffic, although such an occurrence may also be caused by hardware or software. Also called network meltdown.