catastrophe

A catastrophe is a very bad event that causes a lot of damage or destruction.

The word "catastrophe" is often used to describe big disasters like earthquakes, hurricanes, or fires. You might hear someone say, "The city was hit by a catastrophe when a hurricane swept through." It's also used for other kinds of events that are just as bad, but maybe not so sudden – like an economic crisis where many people lose their jobs and homes. In this case, the event is still very bad, even if it happens over time instead of all at once.