crash

a loud resonant repeating noise; "he could hear the clang of distant bells"
a sudden large decline of business or the prices of stocks (especially one that causes additional failures)
(computer science) an event that causes a computer system to become inoperative; "the crash occurred during a thunderstorm and the system has been down ever since"
undergo a sudden and severe downturn; "the economy crashed"; "will the stock market crash again?"