What does brownout mean?
A brownout is a drop or reduction in electrical power that stops short of a total outage: lights may dim, appliances may struggle, and sensitive equipment may malfunction, but the current keeps flowing. The term arose as an informal counterpart to "blackout," evoking the brownish glow of dimmed incandescent bulbs. Brownouts can occur accidentally, when demand outstrips supply and voltage sags on the grid, or deliberately, when utilities impose planned, often rotating reductions — so-called rolling brownouts — to keep a strained system from collapsing entirely. They are most associated with hot weather, when air-conditioning drives peak demand, and with aging or overloaded power infrastructure. For consumers, brownouts are more than an inconvenience: sustained low voltage can damage motors, compressors, and electronics. The word is standard in news reporting on energy policy and grid reliability throughout the English-speaking world.
nounA temporary reduction in electrical power, in which voltage drops or lights dim rather than failing completely; also, a period of restricted electricity use imposed to conserve supply.
- A temporary reduction or sag in electrical voltage that causes lights to dim and equipment to malfunction without cutting off power entirely.
- A deliberate period of reduced or rationed electricity supply imposed by a utility during shortages (often called a rolling brownout).
"The heat wave pushed demand so high that the utility was forced to impose rolling brownouts across the region."
"During the storm the neighborhood experienced a brief brownout, with lamps flickering before the power stabilized."
"To avoid overloading the strained grid, the city scheduled rolling brownouts through the evening peak."
Regular plural; commonly used when discussing repeated or geographically distributed power reductions.
"Utilities warned that brownouts would continue until new generation capacity came online."
The word is a playful cousin of "blackout": when the lights merely dim instead of going out, engineers said the grid had turned brown — and the name stuck.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of brownout
"Brownout" originated in American English during World War II, coined on the model of "blackout" to describe the dimmed lighting used to reduce glare while still allowing some visibility. After the war it settled into its modern sense of a partial reduction in electrical power, as opposed to the complete loss implied by "blackout." The formation follows a common English pattern of compounding a color with "-out" (compare "whiteout"), with the color suggesting something less than absolute darkness.
How brownout is actually used
Informal to neutral register, common in journalism about energy and infrastructure. In American usage especially, "rolling brownout" refers to rotating, planned reductions in service across different areas. Less commonly, "brownout" appears in psychology describing a partial loss of memory for events during intoxication, but the electrical sense dominates.
Easily confused with brownout
A blackout is a total loss of electrical power, whereas a brownout is only a partial drop in voltage or supply.