1 [often with modifier] a failure of electrical power supply:due to a power blackout, their hotel was in total darkness
a period when all lights must be turned out or covered to prevent them being seen by the enemy during an air raid:people found it difficult to travel in the blackout [as modifier]:she peered out through the blackout curtains
(usually blackouts) dark curtains put up in windows to cover lights during an air raid.
a moment in the theater when the lights on stage are suddenly turned off.
2a suppression of information, especially one imposed on the media by government:there is a total information blackout on minority interests
a period during which a particular activity is prohibited:there are no blackout days during the travel period
3a temporary loss of consciousness:she was suffering from blackouts
