koan

noun

1. 1

   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.

2. 2

   A riddle with no solution, used to provoke reflection on the inadequacy of logical reasoning, and to lead to enlightenment.