the extinguishing or concealment of all visible lights in a city, military post, etc., usually as a precaution against air raids.
a period during a massive power failure when the lack of electricity for illumination results in utter darkness except from emergency sources, as candles.
a brief, passing lapse of memory: An actor may have an occasional blackout and forget a line or two.
complete stoppage of a communications medium, as by a strike, catastrophe, electrical storm, etc.: a newspaper blackout; a radio blackout.
a stoppage, suppression, or obliteration: a news blackout.