lasting for a markedly brief time; "a fleeting glance"; "fugitive hours"; "rapid momentaneous association of things that meet and pass"; "a momentary glimpse"
not permanent; not lasting; "politics is an impermanent factor of life"- James Thurber; "impermanent palm cottages"; "a temperary arrangement"; "temporary housing"
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
abrupt electric discharge from cloud to cloud or from cloud to earth accompanied by the emission of light