melt·down 
/ˈmɛltˌdaʊn/ noun
plural melt·downs /ˈmɛltˌdaʊn/ noun 1 : an accident in which the core of a nuclear reactor melts and releases radiation [count] ▪ a nuclear meltdown [noncount] ▪ fears that an accident could cause meltdown 2 a : a very fast collapse or failure [count] ▪ a stock market meltdown [noncount] ▪ a company experiencing financial meltdown
b [count] chiefly US, somewhat informal : a very fast loss of emotional self-control
▪ After a long day at the beach, our toddler had a major meltdown in the car on the way home. — see also melt down at 1melt
b [count] chiefly US, somewhat informal : a very fast loss of emotional self-control
▪ After a long day at the beach, our toddler had a major meltdown in the car on the way home. — see also melt down at 1melt
