Pronunciation: (blak'out"),[key] —n. 1. the extinguishing or concealment of all visible lights in a city, military post, etc., usually as a precaution against air raids.
2. a period during a massive power failure when the lack of electricity for illumination results in utter darkness except from emergency sources, as candles.
3. Theat. a. the extinguishing of all stage lights, as in closing a vaudeville skit or separating the scenes of a play.
b. Also calledblack'out skit". a skit ending in a blackout.
4. Pathol. a. temporary loss of consciousness or vision: She suffered a blackout from the blow on the head. b. a period of total memory loss, as one induced by an accident or prolonged alcoholic drinking: The patient cannot account for the bizarre things he did during his blackout. 5. a brief, passing lapse of memory: An actor may have an occasional blackout and forget a line or two. 6. complete stoppage of a communications medium, as by a strike, catastrophe, electrical storm, etc.: a newspaper blackout; a radio blackout. 7. a stoppage, suppression, or obliteration: a news blackout. 8. a period during which a special sales offer, fare rate, or other bargain is not available: The airline's discount on fares does not apply during the Christmas week blackout. 9. Radio and Television.a prohibition that is imposed on the broadcasting of an event and has the purpose of encouraging or ensuring ticket sales.