번개 • (beon-gae)
First attested in the Worin seokbo (月印釋譜 / 월인석보), 1459, as 번게 (Yale: penkey).
Equivalent to the root 번 (beon, “*bright”) + suffix —게 (-ge, “the thing which”). Related to 번득 (beondeuk, “with a flash”), 번쩍거리다 (beonjjeokgeorida, “to glitter”).