noun

• (slang) A chamber pot enclosed in a box; a portable commode.
  "True, our cash would run out, but Charleton wouldn't let us starve. He'd put us into shorts, and we should wash the dishes and clean the thunder-boxes and take out guests for walks."
• (by extension, chiefly Australia, British, slang) Any lavatory or toilet, especially a rudimentary outdoor latrine or toilet, or an outhouse.
  "Meantime the ICE [Institute of Consumer Ergonomics] experts are poring over their photographs, and making measurements, which, presumably, will go into a computer, and out will come the specification for the perfect thunderbox."
• (theater) A box of metal balls which is shaken to create a thunder sound effect.
  "[T]wo articles, both indispensibly necessary to a theatre, are not blundered, viz. a property room, and thunder box!—no they are omitted altogether!!"

noun

• (military, obsolete) A blunderbuss; also, a cannon.
  "In the year 1346, at the battle of Crecy, the engliſh uſed a ſort of cannons, which were then called thunder-boxes."