(physics) any of four unstable subatomic particles, mesons, they are a combination of a strange quark or antiquark and either an up or down quark or antiquark
koan
koan
noun
(Zen Buddhism) 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.
