köken: Ultimately from Latin lampades, possibly through a derivative of the Late Latin verb lampō, lampāre, with later alterations within early Romance, or from the related lampada. The prefix re- indicates the idea of repetition, hence lightning striking over and over again. Compare Portuguese relâmpago, relâmpado, Catalan llampec.
From Blitz (“lightning”) + Krieg (“war”), coined in the runup to the Second World War to denote the "lightning fast" military campaigns planned by the German forces.