IPA: /dɪˈzæstə/
KK: /dɪˈzæstər/
A serious event that causes a lot of damage, destruction, or suffering.
The earthquake was a disaster that affected thousands of people.
Disaster is formed from "dis-" (meaning apart) and "aster" (from Greek "ἀστήρ" or "aster", meaning star). The term originally referred to a star that was unfavorable, indicating a misfortune or calamity caused by the stars' alignment.
Think of a 'star' ('aster') that is 'unfavorable' ('dis-'), which helps you remember that a disaster is an unfortunate event.