blackout

Blackout is a term with several related meanings. In everyday use, it describes a temporary loss of vision, consciousness, or memory, often caused by injury, illness, or alcohol. It can also refer to the intentional suppression of information or to a period during which electrical power is unavailable.

A blackout in power terms is a loss of electrical power across a region or large area. It can result from damage to infrastructure, severe weather, overloads, or cascading failures in the grid. Blackouts may be planned, such as during maintenance or load shedding, or unplanned, with restoration times ranging from minutes to days.

In medical and psychology contexts, blackout usually denotes a temporary lapse of memory during intoxication, especially alcohol. There are two common forms: fragmentary blackouts, where some memories can be recovered with cues, and en bloc blackouts, where recall of events is completely absent. The term is also used informally for brief loss of consciousness, though that is usually described as syncope or fainting.

A visual blackout refers to temporary loss or obstruction of sight, as can occur with glare, migraine, retinal or neurological conditions, or as part of a medical procedure like controlled lighting.

In media and broadcasting, a blackout is the suppression or blocking of information or the interruption of transmission. News blackouts, sports blackouts, or signal blackouts may be used for safety, censorship, licensing restrictions, or rights management.