3.nounAn instance of censorship, especially a temporary one.
"media blackout"
4.nounA large-scale power failure, and resulting loss of electricity to consumers.
""The repairs at the Koeberg Power Station in the Western Cape were on schedule for completion in the third week of May. This follows huge blackouts related to the problems at the power supplier since November. Weekend Argus May 13/14 2006 p.5."
5.nounThe mandatory blocking of all light emanating from buildings as imposed during World War II.