Definition of "koan" in English

noun

1. (Zen Buddhism) A story about a Zen master and his student, sometimes like a riddle, other times like a fable or parable, 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. A riddle with no solution, used to provoke reflection on the inadequacy of logical reasoning, and to lead to enlightenment.

3. A therapy technique used by Traditional Chinese medicinal physicians or medical practitioners to break a presenting patients habitual pattern of thinking that has been diagnosed as the primary cause of an illness or disease.