thunderbox
A blunderbuss; also, a cannon.
obsolete
In the year 1346, at the battle of Crecy, the engliſh uſed a ſort of cannons, which were then called thunder-boxes.
Where it comes from
Probably a calque of German Donnerbüchse (“(archaic) blunderbuss; cannon”) (from Donner (“thunder”) + Büchse (“box; can; rifle”)), or its etymon Dutch donderbus (“blunderbuss”) (from donder (“thunder”) + bus (“box; container; (chiefly historical) type of early modern firearm”)).
Adapted from the Wiktionary entry thunderbox (CC BY-SA 4.0).