koan
/ˈkəʊ.ɑːn/
noun
Meaning
A story about a Zen master and his student, sometimes like a riddle, other times like a fable, which has become an object of Zen study, and which, when meditated upon, may unlock mechanisms in the Zen student’s mind leading to satori.
A riddle with no solution, used to provoke reflection on the inadequacy of logical reasoning, and to lead to enlightenment.