Dictionary

flashover en · NOUN

Etymology

Deverbal from flash over.

Meanings

1. (countable, uncountable) The near simultaneous ignition of all combustible material in an enclosed area.
   • The blaze turned into what Swiss officials called an embrasement généralisé, a term for a fire that releases combustible gases that can ignite violently, triggering what English-speaking firefighters call a flashover or backdraft. 2026 January 1, Chris Michael, Rory Carroll, “‘It happened in seconds’: sudden inferno brings horror to Swiss ski resort”, in The Guardian, →ISSN:
2. (countable, uncountable) An unintended electric discharge or arc over or around an insulator.
   • The overhead line was energised at 25,000 volts and the height of the contact wire was reduced to 11 in. above the chimney, then to 5 and finally to 2 in.; at this last, short distance the flashover occurred, but all the men were perfectly safe because the current went direct to earth through the locomotive. 1960 April, “Talking of Trains: Safety with 25kV a.c.”, in Trains Illustrated, page 203:

Forms

Deriveds

flashover voltage

Synonyms

sparkover

Translations (9)

sv övertändning (ignition) · fi lieskahdus (ignition) · de Flashover (ignition) · cmn 閃燃 /闪燃 (ignition) · de Überschlag (electric discharge) · ja フラッシュオーバー (ignition) · sv överslag (electric discharge) · fi ylilyönti (electric discharge) · de Raumdurchzündung (ignition)