puzzle-box

Noun

puzzle box (plural puzzle boxes)

1. A box that cannot be opened by the usual obvious means, and therefore challenges a person to find the correct way to open it.
   • "Jest like the Injian puzzle-boxes, ain't they?" said Dan, as the one boat dropped into the other.1896 November – 1897 May, Rudyard Kipling, “Captains Courageous”, Garden City, N.Y.: Doubleday & Company, published 1897, →OCLC
2. A similar device or cage that can be opened by means of levers, latches, etc., used to test the learning behaviour of animals.
   • That’s where Osvath’s ravens come in. His student Can Kabadayi trained the birds to open a baited puzzle box by putting a stone of particular weight and shape into a tube.2017 July 13, Ed Yong, “Ravens Can Plan for the Future”, in The Atlantic
3. (figuratively) Something that is puzzling; an enigma; (narratology, also attributive) a complex story that is gradually revealed, often driven by a central myth.
   • puzzle box show
4. (literally) A box containing a jigsaw puzzle.
   • The world is the geologist's great puzzle-box; he stands before it like the child to whom the separate pieces of his puzzle remain a mystery till he detects their relation and sees where they fit, and then his fragments grow at once into a connected picture beneath his hand.1863 March, The Atlantic Monthly, volume 11, number 65