0 (the state of being ready to deal with) a sudden dangerous situation:
The army was on red alert against the possibility of an attack.
Apart from the date on which the red alert button was first pushed, there is a subsidiary point of great importance.
Red alert status is not a term defined or used by the national health service on a national basis.
Treliske was on red alert when my brother went in, as it often is.
America put scientists at a satellite receiving station on a red alert to make sure that there had been no nuclear leak.
Later that day the first red alert of the season for the island came into force.
Kirk, however, maintains his claim that the ship was at red alert status during the ejection of the pod.
London has had just one week of red alerts.
Every month the hospital is on red alert.
