American English

Definition of red alert noun from the Oxford Advanced American Dictionary

 

red alert

 noun
noun
 
[uncountable, singular]
 
jump to other results
a situation in which you are prepared for something dangerous to happen; a warning of this Following the bomb blast, local hospitals were put on red alert. The mayor has issued a red alert until the cause of the pollution is removed.
See the Oxford Advanced Learner's Dictionary entry: red alert