Brown out as in “no power” (electricity) is a drop in voltage in an electrical power supply, so named because it typically causes lights to dim. A controlled power reduction decreases the voltage on the power lines, so customers receive weaker electric current. Brown outs can be used if total power demand exceeds the maximum available supply. The typical household does not notice the difference.
On December 28, 1965 the New York Times ran a story entitled “Merchants Fight Rome Traffic Ban, Plan Brown-Out of Stores To Force End Of Test.” The first paragraph read:
Merchants in central Rome voted tonight to “brown out” their stores and eventually close them if the city persisted in an experimental curb on movement of private vehicles in a 35-block shopping and residential area.
During World War II, the New York Times published an article on December 11, 1943 entitled, “WPB Aide Assaults Brownout Cheats; Lack Of Voluntary Cooperation In Saving Needed Power Scored By Vanneman.” The first paragraph read:
An end of unnecessary brilliance in the lighting of the Broadway sector and some other parts of the city was urged yesterday by Donald K. Vanneman, government requirements representative of the War Production Board, who said that “too many” business establishments had failed to do their part in the voluntary brownout intended to conserve electric power, coal and other resources.
As you can see, the expression brown out in this instance is a derivative of the expression black out from the World War II era.
See “black out” for additional information.
Historically Speaking 