from
The Collaborative International Dictionary of English v.0.48
brownout \brown"out\ n.
1. darkness resulting from the extinction of lights (as in a
city invisible to enemy aircraft).
Syn: blackout, dimout.
[WordNet 1.5]
2. a partial reduction in the amount of electric power
available to customers in a region, such as by reduction
of voltage or selective cutoff of certain customers; -- it
occurs for example in summer when the demand for
electricity for air-conditioning exceeds the supply, or
when power to certain customers is cut off by a severe
storm. It is contrasted with {blackout}, which is the
total loss of electrical power in a region.
[PJC]