The discharge of atmospheric electrical charge itself, abrupt electric discharge from cloud to cloud or from cloud to earth accompanied by the emission of light, the flash of light that accompanies an electric discharge in the atmosphere (or something resembling such a flash); can scintillate for a second or more, adjective_ Extremely fast or sudden, Moving at the speed of lightning, verb_ rare Lightening, impersonal To produce lightning, intransitive verb_ To discharge a flash of lightning,