noun
also philosopher's stone
Etymology: Middle English philosophres stoon, probably translation of Medieval Latin lapis philosophorum
1. : an imaginary stone, substance, or chemical preparation believed to have the power of transmuting the baser metals into gold, much sought for by alchemists, and by some identified with elixir
2. : a principle or concept capable of achieving the spiritual regeneration of man
exuded confidence that Turkey possessed the political philosopher's stone in its policies of modernization — William Clark