- 1a serious accident in which the central part of a nuclear reactor melts, causing harmful radiation to escape
- 2(economics) a situation where something fails or becomes weaker in a sudden or dramatic way The country is in economic meltdown. a meltdown on the New York Stock Exchange
meltdown
nounBrE BrE//ˈmeltdaʊn//; NAmE NAmE//ˈmeltdaʊn//
[uncountable, countable]Check pronunciation: meltdown