melt·down
ˈmelt-ˌdau̇n
1
: the accidental melting of the core of a nuclear reactor
2
: a rapid or disastrous decline or collapse
warning of a stock market meltdown
3
: a breakdown of self-control (as from fatigue or overstimulation)
an exhausted toddler having a meltdown
melted down; melting down; melts down
1
of a nuclear reactor
: to undergo an accidental melting of the core
2
: to experience a very fast collapse or failure
The stock market melted down today.
: to melt (something) so that it can be used for another purpose
melting down gold coins
Cite this Entry
“Meltdown.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/meltdown. Accessed 4 Sep. 2026.
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