Meaning of “emergency” - Learner’s Dictionary

emergency

noun [ C ] us uk /ɪˈmɜːdʒənsi/
Medical staff are on call in case of an emergency.He was called to an emergency meeting.She had emergency surgery after being rushed to hospital.Many people don't know what to do in an emergency.Leave a number where you can be contacted in an emergency.

B1 a serious or dangerous situation that needs immediate action:

You should only call this number in an emergency.
an emergency exit

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