Meaning of “disaster” - Learner’s Dictionary

disaster

noun us uk /dɪˈzɑːstər/
an environmental disasterThe scale of the disaster is becoming more apparent every day.He was a victim of the Chernobyl nuclear disaster.The plane crash was the worst disaster in the country's history.The disaster brought the community closer together.
DAMAGE [ C ]

B2 something that causes a lot of harm or damage:

floods and other natural disasters
FAILURE [ C ]

B2 a failure or something that has a very bad result:

His idea was a total disaster.
BAD SITUATION [ U ]

an extremely bad situation:

The holiday ended in disaster.

(Definition of “disaster” from the Cambridge Learner’s Dictionary © Cambridge University Press)