thunder. to steal one's thunder
- This idiom, meaning to reduce the effect of a person's words or actionsby forestalling them, originated from an incident involving the Englishplaywright and critic John Dennis (see Appius). Dennis was theinventor of the thunder-run, a device in which cannon balls wererolled down wooden troughs to create a sound effect for thunder (seesound effects).
He introduced the thunder-run in his drama Appius and Virginia,which was produced at Drury Lane in 1709 but was taken off after afew performances. Soon afterwards, while watching Macbeth atthe same theater, Dennis heard his thunder-maker in action. He leapedup, faced the audience, and yelled, "The villians! That's mythunder they're using. They won't play my play, but they will stealmy thunder!"