A puzzling, often paradoxical statement, anecdote, question, or verbal exchange, used in Zen Buddhism as an aid to meditation and a means of gaining spiritual awakening.
[Japanese kōan : kō, public (from Middle Chinese kəwŋ; also the source of Mandarin gōng) + an, matter (from Middle Chinese ʔan`; also the source of Mandarin àn).]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2019 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.