An explanation of the “abroach” image in Act 1, Scene 1 of myShakespeare’s Romeo and Juliet.
Montague
Who set this ancient quarrel new abroach?
Speak, nephew, were you by when it began?
To set something abroach means to pierce a hole in a cask of liquor and let the contents run out. But given the context, this image might be better visualized as gunpowder pouring out of a powder keg.
