an unforeseen occurrence or combination of circumstances that is potentially dangerous and calls for immediate action
(used before a noun) resulting from or used in such a situation
an emergency landing
a patient who with a serious injury or medical condition that needs urgent treatment
Aus, NZ in sport, a player who has been selected to replace another if the need arises, e.g. through injury
[medieval Latin emergentia, literally ‘something that emerges’, from Latin emergere: see emerge]