black·out 
(blăkout′)
(blăkout′)n.
1. A cutoff of electric power, especially as a result of a shortage, a mechanical failure, or overuse by consumers.
2. The concealment or extinguishment of lights that might be visible to enemy aircraft during an air raid.
3.
a. The sudden extinguishment of all stage lights in a theater to indicate the passage of time or to mark the end of an act or scene.
b. A short, comic vaudeville skit that ends with lights off.
4. A temporary loss of memory or consciousness.
5.
a. A suppression, as of news, by censorship.
b. A suppression of the broadcast of an event or program, as to support ticket sales at a local venue.
6. A suspension of a discounted price or free offer, as for an airline ticket or a lift ticket at a ski resort.