- 1a period when there is no light as a result of an electrical power failure
- 2 a temporary loss of consciousness, sight, or memory She had a blackout and couldn't remember anything about the accident.
- 3a situation when the government or the police will not allow any news or information on a particular subject to be given to the public The government imposed a news blackout during the crisis.
- 4 a period of time during a war when all lights must be put out or covered at night, so that they cannot be seen by an enemy attacking by air It used to take hours to travel home in the blackout.
- 5 [usually plural] a covering for windows that stops light from being seen from outside, or light from outside from coming into a room