lightning lightning /ˈlaɪtnɪŋ/

noun

1. () Abrupt electric discharge from cloud to cloud or from cloud to earth accompanied by the emission of light  ( lightning )
   abrupt electric discharge from cloud to cloud or from cloud to earth accompanied by the emission of light
    Lightning struck the tree, splitting it in half and causing a loud thunderclap
   Lightning struck the tree, splitting it in half and causing a loud thunderclap
   
   
2. () 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  ( lightning )
   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
     The lightning illuminated the dark sky during the thunderstorm.
   The lightning illuminated the dark sky during the thunderstorm.