tin·der·box / ˈtindərˌbäks/ • n. hist. a box containing tinder, flint, a steel, and other items for kindling fires. ∎ fig. a thing that is readily ignited: dry winds and no rain have turned parts of the state into a tinderbox. ∎ fig. a volatile situation, or a person who is readily aroused, esp. to anger: the perception of Kosovo as a potential tinderbox within Serbia.