gunpowder (n.) Look up gunpowder at
"explosive powder for the discharge of projectiles from guns," early 15c., from gun (n.) + powder (n.). The Gunpowder Plot (or treason or conspiracy) was a plan to blow up the Houses of Parliament on Nov. 5, 1605, while the King, Lords and Commons were assembled there in revenge for the laws against Catholics (see guy (n.2)).