[U] flash of brilliant light in the sky produced by natural electricity passing between clouds or from clouds to the ground, usu followed by thunder 闪电: be struck by lightning 遭雷电击中 * a flash of lightning 一道闪电. 
(idm 习语) lightning never strikes in the same place twice (saying 谚) an unusual event, or one that happens by chance, is not likely to occur again in exactly the same circumstances or to the same people 偶发的事不会在同一环境或同一人身上重演. like (greased) `lightning; like a streak of lightning; (as) quick as `lightning very fast 很快.# `lightning-bug n (US) firefly 萤火虫.
`lightning conductor (Brit) (US lightning rod) metal rod or wire fixed to an exposed part of a building, etc to prevent damage by lightning 避雷针.