a box containing dry material, used in the past for lighting a fire (旧时点火用的)火绒盒,引火盒 - (formal)
a situation that is likely to become dangerous 一触即发的形势 It was clearly a tinderbox situation with demonstrators likely to become violent at any moment. 这显然是一个火药桶,示威者随时都可能变得暴力。